Apparatus and method for a cellular freeway emergency telephone

Apparatus and method for a cellular freeway emergency telephone
United States Patent [191
Franklin et a1.
Patent Number:
Date of Patent:
Dec. 27, 1994
Fichout, J. et al. “New Services for the IRT 1500 sub
scriber Connection System”, Communication and
Transmission, No. 2, pp. 25-38 (1985).
Janttl, K, “Emergency Telephone System $05,] 12”,
[75] Inventors:
G. Franklin; Scott Ward, both
of La Habra; George R. Mabry,
Hesperia, all of Calif.
[73] Assignee:
Cellular Communications
Ericcson Review, No. 3, 1982.
Komura M. et a1. “Subscriber Radio Telephone System
for Rural Areas”, Japanese Telecommunications Re
view, vol. 18, No. 2 pp. 91-100 (Apr. 1976).
Corporation, Irvine, Calif.
Kuchel, J. “Rural Radio Telephones with Solar Power
Supply”, (date unknown) pp. 91-96.
[211 Appl. No.: 186,099
Jan. 25, 1994
[22] Filed:
Sanchez, A. 6., “Design of a Multiple Access Radio
System for Rural Telephony”, Telecommunication
Journal, vol. 50, XI pp. 615-621 (1983).
Vlamincky, L., “ATEA Police Call System”, The Au
tomatic Electric Technical Journal, vol. 4, No. 1 (Dec.
Related US. Application Data
Continuation of Ser. No. 415,491, Sep. 28, 1989, aban
doned, which is a continuation of Ser. No. 255,754,
Oct. 11, 1988, abandoned, which is a continuation of
Ser. No. 801,410, Nov. 25, 1985, Pat. No. 4,788,711.
Int. Cl.5 .......................................... .. H04M 11/00
US. Cl. ...................................... .. 379/59; 379/63;
Field of Search ..................... .. 379/59, 56, 60, 45,
Primary Examiner-James L. Dwyer
Assistant Examiner-Ahmad F. Matar
~Attorney, Agent, or Firm-Ni1sson, Wurst & Green
379/45; 455/331
379/58, 63, 38, 39, 40, 42, 48; 340/287, 291;
comprises a controller coupled to a cellular transceiver.
The controller is also coupled to a solar array and bat
tery which is recharged through the controller. The call
box communicates through a radio-telephone link estab
lished by cellular transceiver to a cellular telecommuni-_
cation system. The cellular telecommunication system
includes a call site controller and mobile telephone
switching terminal. Each call box comprises a plurality
3,207,849 9/ 1965 Andrews .
3,441,858 4/1969 Graham .
3,549,810 12/1970 Driscoll et al. .
Friberg et a1. .
(List continued on next page.)
of status subcircuits for monitoring conditions such as
battery condition and transmitter status. The call box
communication and the status are processed by a micro
5944133 12/1984 Japan .
60-84031 5/1985 Japan.
The call box is solar powered with battery storage and
References Cited
A self-contained cellular emergency roadside call box is
disclosed without the use of external telephone lines.
7/1984 United Kingdom .
Cranston, T. K. et a1. “Characteristics of Motorist Aid
Communications System”, IEEE Transactions on Ve
hicular Technology vol. VT-l9, No. 1 (Feb. 1970).
DeNigris, et al., “Enhanced 911:Emergency Calling
processor which generates appropriate commands re
quired by the cellular transceiver. Information can be
transmitted bidirectionally between each of the call
boxes and the communication applications processor.
An interactive ?ow of information is exchanged with
the call box and the functional condition is monitored.
23 Claims, 10 Drawing Sheets
with a Plus”, Bell Laboratories Record, Mar. 1980.
H, mm
r 20
1002mm 1
.mm mm
Page 2
3,622,99911/1971 Getz, Jr. et 21..
9/1972 McMurray .
3,800,089 3/1974 Reddick '
3,844,840 10/1974 Bender _
3,939,417 2/1976 Cannalte et a1. .................. .. 340/505
3,986,119 10/1976 Hemmer, Jr. et a1. .
4,040,013 8/1977 Carlson ............................. .. 340/164
2/1983 Hilligoss, Jr. et a1. . 1
9/1983 May- ' _
4,415,770 11/1983
K31 Ct 3.1. .
4,092,600 5/1978 Zimmermann 6881..
4,511,887 4/1985 Fiore
4,117,404 9/1973 Marshall,
4,131,849 12/1978 Freeburg e181. .
4,176,254 11/1979
Tuttle et a1. ........................ .. 379/45
4,417,100 11/1983 Carlson et a1. .
4,444,661 11/1983 Karlstrom .
4,451,699 5/1984 Gruenberg
4,465,904 8/1984 Gomegen 9* a1- 4,467,142 8/1984 RuPP 9t 81-
8/1985 Harvey etal. .................... .. 340/521
3/1986 Millsap et 41 ~
8/1980 Birilli et a1. .
7/1982 Stenhuis et 31..
6/1987 Paneth et a1. .
2/1988 Farrell ................................. .. 379/59
Winters '
8/1982 Akerberg .......................... .. 340/539
4,788,711 11/1988
US. Patent
Dec. 27, 1994
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Sheet 10 of 10
power to the controller and transceiver; and a solar
array for generating power coupled to the controller
for recharging the battery. Also included in the system
is a cellular telecommunications subsystem in radi
This application is a continuation of applicant’s appli 5 otelecommunication with each of the plurality of emer
cation Ser. No. 07/415,491, ?led Sep. 28, 1989, for “Ap
gency call boxes. A communication applications pro
paratus and Method for Cellular Emergency Freeway
cessor is coupled to the cellular telecommunications
Telephone Service (now abandoned)”, which itself is a
subsystem for processing data received in part from the
continuation identically-titled application Ser. No.
plurality of emergency call boxes. The communications
07/255,754, ?led Oct. 11, 1988, now abandoned, which 10 applications processor communicates through the cellu
is a continuation of identically-titled application Ser.
lar telecommunications subsystem with selected ones of
No. 06/801,410, ?led Nov. 25, 1985, issued as US. Pat.
the plurality of emergency call boxes. By reason of this
No. 4,788,711 and reissued as US. Pat. No. Re. 34,496.
combination of elements the plurality of emergency call
boxes can be installed and maintained at low cost and
15 are capable of arbitrarily programmable interactive
1. Field of the Invention
The invention relates to the ?eld of cellular telephone
The system further comprises interof?ce local tele
equipment and in particular to solar powered telephone
phone exchanges coupled to the communication appli
call boxes using a cellular telephone system to radiotele
cations processor wherein communication between the
phonically communicate from a plurality of ?xed road 20 plurality of emergency call boxes can be selectively
side sites.
coupled to the local telephone exchanges under control
2. Description of the Prior Art
of the communication applications processor.
Emergency roadside call boxes have become increas
The controller comprises a plurality of status subcir
ingly important and productive elements in providing
cuits. Each status subcircuit monitors a predetermined
roadside security and emergency assistance in the met 25 status parameter of the corresponding call box.
ropolitan areas in the United States and throughout the
The system further comprises a circuit for selectively
world. Originally, such roadside emergency call boxes
communicating the predetermined parameters as moni
were hardwired to conventional telephone land lines.
tored by the plurality of status subcircuits to the com
However, the installation of such telephone land lines
munication applications processor. The parameters
substantially escalates the installation and maintenance 30 monitored by the status subcircuits include battery
costs of such emergency roadside telephone boxes. In
power level, and the physical condition of the corre
sponding call box indicative in part of whether call box
has been struck.
The controller further comprises a circuit for receiv
order to overcome this limitation, the prior art devised
emergency telephone call boxes which use a radio
transmission link for communications. Cannalty et 211.,
“Emergency Communications System”, US. Pat. No. 35 ing andprocessing information from the communica
3,939,417; and Wisniewski, “Emergency Calling Sys
tion applications processor to initiate operations in the
tem”, US. Pat. No. 3,492,581 show such systems.
Power for these call boxes is provided by a recharge
The controller still further comprises a circuit for
able battery included within their housings. However,
adjusting the volume of transmitted and received audio
such prior art battery operated systems either required 40 information.
the units to be coupled to a source of electrical power
The controller has a timing mechanization included
for trickle-charging or required the periodic replace
within its digital circuitry. The timer provides he capa
ment or recharging of the battery packs through mobile
bility to measure predetermined elapsed time periods.
roadside service. Again, although savings were realized
The timer mechanism is used in the following ways:
in installation costs by using battery powered units, the
1) To limit each call to a maximum duration (e.g. 10
maintenance or service costs of such systems often pro
hibited their use.
2) To terminate a call if there is no conversation for a
Furthermore, in the past radiotelephone communica
predetermined period of time (e. g. one minute); and
tions within geographic areas were realized using a
process based on a single transmitter and antenna. This 50
method of communication limits the number of calls
that can be placed in a geographic area and limits the
size of the area that can be covered with a given amount
of equipment. However, with the recent advent of cel
lular telephone technology, these limitations, which
3) To cause each call box to automatically initiate a
call and to report its operational stats on a periodic
basis (e. g. once every 24 hours).
In the event that the telephone handset is left off the
hook, the automatic time out will terminate the call and
will thus save battery power. Should this occur, the call
box is automatically reactivated and another emergency
call is placed should the hook switch be operated to the
were characteristic of the prior art single transmitter
systems, no longer exist.
on-hook status followed by an off-hook status.
Therefore, what is needed is a design and method of
Stated in yet another way the invention is an emer
using a radio linked emergency call box which is adapt
gency roadside call box comprising: a controller; a cel
able to cellular telephone technology and which is char 60 lular transceiver coupled to and controlled by the con
acterized by low installation and service costs.
troller; a battery for powering the controller coupled to
the controller and transceiver; and a solar array coupled
to the controller for recharging the battery. By reason
The invention is a system for providing an emergency
of this combination of elements an emergency roadside
call box service comprising a plurality of emergency 65 call box can be installed and maintained at low cost.
call boxes, wherein each call box further comprises: a
The controller comprises a plurality of status subcir
controller; a cellular transceiver coupled to the control
cuits for monitoring corresponding selective parameters
ler; a battery coupled to the controller for providing
of the controller, and a circuit for interrogating the
plurality of status subcircuits for operationally respond
ing to the parameters as monitored by the status subcir
The plurality of the subcircuits comprise at least a
subcircuit for monitoring a user request for emergency
transmission, battery condition, presence of a communi
cation transmitted to and from the call box, physical
integrity of the call box.
The call box further comprises a circuit for selec
tively communicating the corresponding plurality of
FIG. 4 is a block diagram of including the controller
in the call box and its associated system elements.
FIG. 5 is a schematic diagram of status subcircuits
included in the controller.
FIG. 6 is a schematic diagram of another status sub
FIG. 7 is a schematic diagram of a circuit to read the
status data.
FIG. 8 is a schematic diagram of a programmable
microprocessor incorporated in the controller.
FIG. 9 is a schematic diagram of decoder circuit used
parameters of the call box to an off-site recipient.
to communicate between the microprocessors on the
The call box still further comprises a circuit for re
ceiving information generated off-site and a circuit for
FIG. 10 is a schematic diagram of a circuit for cou
initiating an operation of the call box in response to the
15 pling signals between the transceiver and one of the
received off-site information.
microprocessors on the controller.
The controller comprises a circuit for conserving
FIG. 11 is a schematic diagram of an audio level
power from the battery when an emergency communi
adjust circuit which can be controlled by a remote
cation is not desired, and a circuit for adjusting audio
central processor.
gain for audio information transmitted and received by
FIG. 12 is a ?ow diagram illustrating the operation of
the call box.
the controller.
The invention can still further be characterized as a
The invention and its various embodiments may be
method in an emergency roadside call box, where the
better understood by now turning to the following de
call box is battery powered and coupled through a radi
otelecommunication link to a cellular telecommunica
tion system and communication applications processor. 25
The method comprises the steps of reading a plurality of
call box status parameters. Next follows the step of
selectively performing a remedial routine in response to
the step of reading the plurality of status parameters
dependent upon the condition of each corresponding
parameter. Thereafter follows the step of selectively
entering an emergency call routine wherein a cellular
Before considering the detailed circuitry in the cellu
lar call box and its method of operation, ?rst generally
consider the environment in which the call box is used
and how it is utilized during normal operation.
Turn now to FIG. 1. When an emergency occurs
along a roadside, the affected user will locate the near
telecommunication transceiver within the call box is
est emergency call box, generally denoted by reference
powered up and bidirectional voice communication is 35 numeral 10. The user will lift the handset which will
established through the cellular telecommunication
cause call box 10 to automatically dial a prepro
system to the communication applications processor.
By virtue of this method, remotely powered emergency
call boxes in radio-telecommunication with he commu
nication applications processor are operationally main
grammed number co the freeway emergency telephone
system control center. The call is transmitted via a radio
link to a local cell site transceiver 12 over a selected one
of 21 channels according to which channel is the stron
gest cellular channel available. This selection of com
munication channels by transceiver 12 and mobile tele
apparatus in combination with a cellular radiotelephone
phone switching of?ce 14 is well known in the art of
generating information compatible with the cellular
cellular communications and will not be further de
radiotelephone in a solar powered emergency call box. 45 scribed. Local cell site transceiver 12 is connected with
The invention comprises a ?rst circuit for determining a
a mobile telephone switching of?ce 14 by wireline
plurality of status conditions relating to the emergency
trunks. Mobile telephone switching of?ce 14, which is
call box; a second circuit for controlling power usage of
an automatic terminal, then provides call box identity
the emergency call box to minimize power usage; and a
con?rmation and predialed access to the control center,
third circuit for processing the status conditions deter 50 which includes a communications applications proces
mined the ?rst circuit and responsive to at least the
sor generally denoted by reference numeral 16. Mobile
status conditions controlling the second circuit. The
telephone switching of?ce 14 can also connect call box
third circuit also selectively bidirectionally generates
10 to a conventional telephone switching exchange 15
The invention can still further be characterized as an
and receives cellular radiotelephone compatible signals
in response to commands from the control center so that
under programmable control. The third circuit is cou 55 three party telephone conference calls can be provided
pled to the ?rst and second circuit and to the cellular
or the call from call box 10 simply handed off to another
The invention is best understood in the context of an
illustrative example as shown in the following drawings
telephone station.
The incoming calls will be uniquely identi?ed with a
speci?c emergency call box. The identi?cation will then
wherein like elements are referenced by like numerals. 60 be used to access a data base and all information corre
sponding to that call box will be retrieved in the appli
cations processor 16. An automatic call distributor 18
FIG. 1 is a block diagram of a system in which the
will connect the incoming call to an available operator
call box incorporating the invention is included.
at a communications applications processor (CAP) sup
FIG. 2 is a front elevational depiction of the call box 65 port station 20. A human operator answers the call and
as installed at a roadside site.
the communication which to this point has been digital
FIG. 3 is a side elevational view of the call box of
will be followed by voice communication. Speci?c call
FIG. 1.
box information will be displayed on the screen in re
sponse to an automatic call distributor processor 22
coupled with a master processor 24 which causes spe
ci?c information to be brought up from the data base to
the appropriate support station 20. Such information
completeness of explanation. First consider the receive
circuitry of the transceiver. In the transceiver discussed
in the illustrated embodiment, radio signals in a prede
includes the location of the call box, nearest access
termined range are selected by a 6-pole bandpass ?lter.
The modulated receive signal is then passed to a pream
roads, local terrain and appropriate local emergency
numbers. Support station 20 and master processor 24
interactively communicate so that all subsequent ac
pli?er. A 3-pole ?lter, which further bandpass ?lters the
receive signal, is coupled to the output of the preampli
tions which are undertaken by the operator can be
logged for archival, management and planning use.
Archival discs 26 are coupled to and controlled by
master processor 24 for mass data storage.
?er. A ?rst mixer is coupled to the 3-pole ?lter. An
injection signal is generated by a receiver synthesizer
and mixes with the receive signal to provide a ?rst IF
signal. The IF signal is then coupled to an IF board.
The IF signal (45 Mhz) is coupled to a buffer ampli?er
whose output is coupled to a 2-pole crystal ?lter which
Turn now speci?cally to call box 10 as shown in FIG.
2 in front elevational view and in FIG. 3 in side eleva
tional view. Call box 10 is a completely self-contained
unit requiring no connection with external power lines
passes the signal on to a second buffer ampli?er. The
output of this buffer ampli?er is coupled to a second
or telephone cables. Box 10 is solar powered, is de
signed for use with a cellular telephone system, and is
coupled to a circuit which includes a second mixer, an
2-pole ?lter. The output of the second 2-pole ?lter is
IF ampli?er, a receiver signal strength indicator, and a
characterized by low-cost installation with quick repair
FM detector. A second conversion and detection is
or replacement.
20 executed in this circuit and its output is an audio signal
As shown in FIGS. 2 and 3, call box 10 comprises a
which is coupled to an audio/logic board. On the audi
housing 28 mounted on a road standard 30. Housing 28
o/logic board the audio receive signal is conditioned in
includes the call box controller, radio transceiver and
battery described and shown diagrammatically in the
a conventional manner.
coupled to a conventional collinear antenna 32 with 3
board. This hybrid comprises a buffer and a 300 Hz to 3
An audio signal from the handset is coupled to the
following FIGS. The three watt radio transceiver is 25 radio via a transmit audio hybrid on the audio/logic
dB of isotropic gain mounted on the top of standard 30.
kHz bandpass ?lter. The output from the bandpass ?lter
Also mounted with antenna 32 is a solar panel 34. Solar
of the transmit audio hybrid is fed to a 2:1 compressor
panel 34 as described below is coupled to circuitry
comprised of one half of a single IC compander located
within man housing 28 and is used to recharge the batter 30 on the audio/logic board. The compander dynamically
included within the housing. In particular, solar array
34 is made of thirty-four matched silicon solar cells with
peak power rated at 10.5 watts. The panel is glass lami
nated and held in a metal frame to protect it from dirt,
condenses the audio signal, which is expanded 1:2 by
the cell site controller to the original dynamic range.
The output of the compressor is fed back into the trans
mit audio hybrid, which contains circuitry for preem
moisture impact. Approximately 2.2 watt hours per day 35 phasis, limiting, ?ltering, audio muting, and a summing
is generated on the average by the solar panel 34, which
ampli?er to combine the transmit audio signal with
is equivalent to the amount of power for 45 minutes of
constant air time, generally estimated to be equal four to
?ve average roadside emergency calls. Standard 30 is
coupled to a ground anchor 36 to embed it into the site.
Ground anchor 36 and standard 30 are coupled together
by break plate 38 seen in FIG. 2 so that, if a vehicle
data, supervisory audio tones and other control signals
before outputting the signal to the synthesizer digital
board. The transmit audio signal is coupled to the mod
ulation input of a sidestep VCO on the synthesizer
board. The output of the VCO a modulated 30 MHz
signal, is coupled to a buffer whose output is coupled to
one input of a sidestep mixer. The injection input on the
mixer is provided with a signal which is an output fre
collides with standard 30, break plate 38 will bend,
retain standard 30 to the ground anchor 36, and allow
standard 30 to be folded over instead of being snapped 45 quency doubled from the receive VCO. The output of
over the hood and thrust through the windshield of the
the mixer is a modulated RF signal. The RF signal is
oncoming vehicle. Standard 30 is generally U-shaped so
then coupled through a 3-pole ?lter, and ampli?er be
that the coupling antenna and power lines between
fore being coupled to a RF power ampli?er.
housing 28 and solar array 34 antenna 2 are laid in the
The frequency synthesizer comprises a receiver
U-shaped channel of standard 30 and can be covered or 50 VCO, a synthesizer digital board, and an exciter board.
weather sealed by protective plate 35. The entire unit
therefore comprises a sealed and weatherproof assem
The three watt cellular transceiver enclosed within
main housing 28 is a conventional Motorola cellular
transceiver sold under the trademark, DYNA-TAK
2000. The details of operation of the transceiver are
The operating frequencies in the radio are all derived
from the receiver VCO phase-locked loop. This is com
prised of a dual modulus prescaler, a programmable
PLL IC, a charge pump, loop filter, and receiver VCO
hybrid. This loop is controlled by a channel select line
from the logic circuitry which serially loads the channel
select data into the programmable PLL IC. One output
only implicitly included in this description and will not
of the receiver VCO goes through a frequency tripler
be expressly discussed except to the extent necessary for
and is fed to the injector doubler hybrid used in the ?rst
a fully illustrated description. Further details of the 60 mixer of the RF receive circuitry. The other output
transceiver of the illustrated embodiment can be found
from the receive VCO is coupled to a frequency dou
in the published user’s manual, entitled DYNA T.A.C,
bler on the exciter board and serves as the input signal
Cellular Mobile Telephone, 800 MHz Transceiver,
to the sidestep mixer.
available from Motorola Technical Writing Services at
Further details and schematics of all the above cir
1301 E. Algonquin Rd., Schaumburg, Ill. 60196 which 65 cuitry can be found in the Motorola User’s manual
is expressly incorporated herein by reference.
referenced above.
Although details of the transceiver are incidental to
The transceiver signals which are referenced most
the invention, a general description is provided here for
often in the disclosure of the illustrated embodiment are
the handset signals. The handset includes a cradle mi
croprocessor which provides an interface between the
microprocessor of the handset and the microprocessor
of the transceiver logic unit. Digital communication is
effectuated through the digital signals C DATA, T
DATA and R DATA. Data carried by the bus conven~
tion include keypad and ?uorescent display information
for the handset, display information for the cradle con
trol/indicator board, and other various control signals
and commands between the control unit and transceiver
logic unit. Only the more relevant of these signals will
(6) controlling and regulating all timing functions to
integrate the various portions of the assembly;
(7) controlling and regulating the recharging rates
from solar array 34;
(8) controlling all power for the entire assembly de
picted in FIG. 4 in a manner designed for the most
efficient conservation and use of power;
(9) interfacing to transceiver 44; and
(10) providing necessary logic and interface for op
tional controller functions and future enhance
ments such as slow scan video or specialized data
mation or data depending on the state of a control line
INT SELECT. The handset processor uses this cir
Controller 42 is built around a microprocessor 118
described in connection with FIG. 8. A number of sig
nals indicative of the status of call box 10 are coupled to
cuitry to determine if the information on the T DATA
line is actual data or merely a timing pulse. C DATA
and T DATA, or C DATA and R DATA (the choice
processor 118 is coupled and are generated by a plural
ity of status circuits described in FIGS. 5 and 6. Micro
be discussed below. Logic gates are provided in con
junction with the bus signals to gate either timing infor
depending on the direction of information ?ow) will be
logical complements during data transmission. When
they are not so related, they will signify timing informa
tion, i.e. the reset or idle states. Communications with
these signals is on a three wire bidirectional bus. Data is
communicated in an address-then-data serial word for
a data bus 116 as described in FIG. 7 to which micro
processor 118 generates a number of discrete control
signals through a decoder 130 (FIG. 8) for the control
of these status circuits and control signals which are
utilized in a decoder tree in FIG. 9 to provide key pad
and other cellular control signals to cellular telephone
transceiver 44.
Input and output to cellular telephone transceiver 44
mat. At the beginning of communication the bus direc 25
effectuated by the keypad signals shown
tion is established. During message transmission each
coupled to the input/output bus in FIG. 9 and by the
data state is followed by an idle state with a reset state
digital signals, C DATA, T DATA, and R DATA
entered after the last data bit of the message. Further
described below in connection with microprocessors
details of the bus protocol are described in the Motorola 30 118 and 166. Cellular telephone transceiver 44 commu
User’s manual referenced above.
nicates with microprocessor 118 through a second or
Keypad data is communicated from the handset via
interfacing microprocessor 166 described in FIG. 10.
column and row signals which are then used with an
Both microprocessors 118 and 166 control the transmit
internal look-up table to identify the keypad button
which was pushed.
Handset 40 is diagrammatically depicted in FIG. 2.
No further detailed discussion of the transceiver will be
undertaken except to such extent as such details affect
the operation of the cellular call box controller also
included in housing 28. The controller is a single board
circuit which can be easily removed from a modular pin
connector and a new board inserted for easy ?eld ser
vice. The controller comprises the logic and circuitry
necessary to control the entire operation of call box 10.
and receive audio level control circuitry shown in FIG.
35 11. The overall operation of microprocessor 118 is sum
marized by the ?ow chart of FIG. 12.
Turn now to FIG. 5 wherein the operation of these
functions can be provided by the circuitry illustrated.
FIGS. 5-7 are schematics of several circuits which are
controllably used to sense a number of status conditions
of call box 10. For example, the charged condition of
battery 46, the physical integrity of call box 10, the
presence of information on the communication channel,
the status of handset 40, and the condition of the trans
Turning to FIG. 4, a diagrammatic depiction of the 45 mitter are all monitored and selectively reported by
elements within call box 10 is shown. Cellular call box
means of the circuitry which will now be described in
controller 42 serves as the central unit to which solar
connection with the following Figures.
Consider first the battery condition circuit depicted
array 34, battery 46 and any additional call box switches
or input/output functions 48 are coupled. Similarly,
in FIG. 5. Battery 46 is coupled to node 50. A conven
cellular transceiver 44 is coupled to controller 42 and 50 tional voltage regulator, generally denoted by reference
antenna 32 in turn is coupled to cellular transceiver 44.
numeral 52 converts the 13 volts DC. to 5 volts for use
Before describing the circuitry of controller 42, con
throughout the logic circuitry as indicated. The battery
sider ?rst the functions which controller 42 performs.
voltage at node 50 is monitored by a conventional zener
Included among, but not limited to these functions are:
diode 54. If the voltage is sufficient, transistor 56, whose
(l) controlling operation sequences for user friendly 55 input is coupled to the anode of diode 54, will be biased
(2) automatically powering the transceiver when
handset 40 is lifted;
(3) automatically dialing the preprogrammed number
on and its output coupled through two inverters, collec
tively denoted by reference numeral 58, to the set input
terminal, SD, of a clocked latch 60. The output, Q, of
latch 60 is provided with the signal, inverted LO BAT
or alternatively any one of a plurality of numbers
(low battery), which is utilized in subsequent circuitry
corresponding to one of a corresponding plurality
of activated switches or buttons (not shown in the
as described below. Whenever LO BAT is true, a pre
determined low battery voltage or state of battery dis
charged is indicated. The clock input, CP, of latch 60 is
(4) automatically powering down after a preset, pre
provided with a signal, SET LO BAT (set low battery).
programmed time period or after hang-up of hand 65 Latch 60 is cleared by a signal, CL LO BAT (clear low
set 40;
battery), coupled to the clear terminal, CD, of latch 60.
(5) controlling and adjusting necessary voltage level
changes in audio and logic circuits;
Consider now the circuitry in FIG. 5 which monitors
the physical condition of call box 10, namely whether
standard 30 is down on the ground. A mercury tilt
HK. This allows the program to recognize that a call
switch 62 is coupled between the ?ve volt supply and
ground an is normally closed. However, should the pole
was attempted and to enter a call ready status for a
predetermined time regardless of the actual hook condi
be struck, or otherwise tilted, switch 62 will open as
shown in FIG. 5. When switch 62 opens, a high or true 5
Turn now to FIG. 7. The various status signals de
signal will be coupled to the set terminal, SD, of
scribed in connection with FIGS. 5 and 6, OFF HK,
clocked latch 64 whose output, Q, is the signal, DWN
(down), representing that the pole is down. The clock
input, CP, is the signal, SET DWN (set down), and
latch 64 is cleared at its clear terminal, CD, by the signal
CL DWN (clear down).
Turn now to the circuitry in FIG. 5 used to monitor
the status of the rf transmitter. When transceiver 44 is
turned on, 9 volts are applied to node 72. This in turns
on transistor 74 whose output is coupled through in
verter 76 to provide the signal, inverted TRANS PWR
(transmitter power), indicative that the transmitter is
powered up. Again, TRANS PWR is used in circuitry
are each provided as inputs to an encoder 114. The
output of encoder 114 is coupled to a data bus 116 as a
parallel 8-bit word described in more detail in connec
tion with FIG. 8. The remaining portions of the cir
cuitry of FIG. 7 will be described below.
Turning’to FIG. 8, the encoded word in data bus 116,
which is diagrammatically shown throughout the cir
cuitry as appropriate, is coupled to inputs B0-B7 of
microprocessor 118, which is the operational pro
grammed microprocessor of controller 42. Micro
processor 118 in the illustrated embodiment is a Motor
to be described below as a status signal indicative of the
ola 6805 CMOS device which is characterized by very
operation of call box 10.
20 low power consumption. Microprocessor 118 is
Consider now the circuitry in FIG. 5 used to selec
clocked by a conventional external crystal controlled
tively power up the rf transmitter, which as a primary
clocking circuit, generally denoted by reference nu
power user, is normally off. A signal, RLY ON (relay
meral 119. The program for microprocessor 118 is
on), generated by means described below, is applied to
stored within an external EPROM memory 120. Mem
a Darlington pair, generally denoted by reference nu 25 ory 120 is accessed by microprocessor 118 through
meral 94, to selectively energize a relay 96. When relay
terminals B0-B7 and A8-A12 which provide a thirteen
96 is energized in response to RLY ON, the 13 volts of
power at node 50 is coupled through contacts 98 to a
bit access word. Terminals B0-B7 are used during the
?rst half cycle of processor 118 as the lower eight bits of
the address and during the second half cycle as a data
plurality of power terminals IGN SENSE, BAT PLUS,
BAT PLUS TRANSCEIVER POWER, utilized else 30 input-output. Therefore, during the memory fetch, the
where in the circuitry as an operative means of power
lower eight bits of the address are coupled through data
ing up transceiver 44. These power voltages are particu
bus 116 to a bit latch 122 under the control of the ad
lar to the Motorola transceiver assumed in the illus
dress strobe signal from terminal AS of processor 118.
trated embodiment and are thus not further discussed
Thereafter, all thirteen bits of the address are coupled to
35 address bus 124. The address inputs A0—A10 of memory
Turning your attention to the circuitry of FIG. 6
120 are thus coupled to address bus 124 and memory
consider now the status of the operation of handset 40.
120 enabled by address bits A11 and A12 through
The audio portion of the signal from handset 40 is cou
NAND gate 126 and strobed by the output of NAND
pled through capacitor 78 to a peak-to-peak detector,
gate 128. Memory 120 is selectively strobed in a read or
generally denoted by reference numeral 80. The output 40 write cycle according to software control through the
of peak-to-peak detector 80 is coupled through a buffer,
read/write terminal, inverted R/W, and data strobe
generally denoted by reference numeral 82, to the set
input, SD, of clocked latch 86. The output, Q, of latch
86 is the signal, BSY (busy), which indicates that infor
terminal D5 of microprocessor 118 which are provided
as the inputs to NAND gate 128.
Upon power up and reset the internal address register
mation, conversation, or at least an audio signal of some 45 of microprocessor 118 is set at the highest address of 2K
sort is being provided to handset 40. The clock input,
EPROM memory 120. The program is stored in two
CP, of latch 86 is the signal SET BSY (set busy) and
kilobytes of memory. Thus A12 and All are provided as
latch 86 is cleared at its clear terminal,CD, by the signal,
the inputs to NAND gate 126 whose output is coupled
CL BSY (clear busy).
to the inverted chip enable terminal, CE. Thus the two
The means for originating various status signals now
highest address bits serve as an address enable. The
having been described, the primary status signal,
control and timing of microprocessor 118 with respect
namely the lifting of the handset off its hook switch, can
to memory 120 is conventional and will not be further
be considered. Conventional telephone hook switch 100
detailed beyond that just outlined. At any rate, memory
in FIG. 5 senses the lifting of handset 40. One terminal
120 is appropriately strobed and stored information is
of the switch 100 is coupled to ground and the remain 55 then read from outputs Q0-Q7 onto data bus 116. The
ing terminal is coupled to a debounce NAND gate
signals data strobe, DS, and the read/write signal,
latch, generally denoted by reference numeral 102. The
R/W, from microprocessor 118 are similarly coupled to
output of latch 102 is the status signal, OFF LAT (off
the inputs of NAND gate 128, whose output then serves
latch), which is also used as a clocking signal for
as an output enable signal coupled to the inverted out
clocked latch 106. The input, D, of latch 106 is coupled 60 put enable terminal of EPROM memory 120. Thus, data
to the S-volt power supply so that upon receipt of a
from memory 120, as well as encoder 114, is appropri
clock pulse, OFF LAT, output Q of latch 106, the sig
ately made available to microprocessor 118 over data
nal, OFF HK (off hook), goes high. Latch 106 is cleared
bus 116.
at its clear terminal, CD, by a signal, CL OFF HK
Outputs PAO-PA7 and PBO~PB7 are input/output
(clear off hook). Thus once the handset has been taken 65 ports of microprocessor 118 which in the present em
off hook, the circuitry will be able to remember that this
bodiment are used only as output terminals which are
has occurred even if placed back on hook until Latch
selectively accessed through a program control. Con
106 is cleared by program control through CL OFF
sider now the various outputs provided at these termi
nals. PAS-PA7 and PBS-PB7 are coupled to the inputs
of decoder 130. The signals at the outputs of PAS-PA7
correspond respectively to two encoded bits designated
A11 to the inputs of NAND gate 148. The output of
NAND gate 148 is logically combined in OR gate 150
with the output of NAND gate 128, the inverted signal
DS/R. The output of OR gate 150 in turn is coupled to
the inverted output enable terminal, OE, of encoder
114. Therefore, the output word from encoder 114 is
coupled to data bus 116 according to the logic provided
by gates 144. This logic prevents the placement of a
as AUA and AIA and an inverted enable signal, EX.
Similarly, signals PBS-PB7 include respectively two
encoded bits AOB and AIB together with an inverted
enable signal EB. These data bits and their respective
enable signals are thus coded according to conventional
means into a plurality of control signals as illustrated in
status word on data bus 116 at the same time that the
FIG. 6. For example, the signals CL OFF HK, SET B,
program is being read from memory 120.
Turn now to FIG. 9 wherein signals, A0—A4, gener
CL LO BAT which were described in connection with
ated on control bus 132 by microprocessor 118 are con
various status latches of FIG. 4 are generated by micro
verted into row and column key pad signals which can
processor 118 in combination with decoder 130. The
be understood by transceiver 44. The signal A4 on con
various latches are thus clocked and cleared at the ap
trol bus 132 corresponding to the output from terminal
propriate times under software control as the status of
PA4 of microprocessor 118 is an enable signal used to
call box 10 is queried.
enable decoder 154. Decoder 154 is driven by the con
Outputs PAIL-PA4 of microprocessor 118 are cou
trol signals A2 and A3 corresponding respectively to
pled to a control bus 132 to respectively generate con
terminals PA2-3 of microprocessor 118. The output of
trol signals A0-A4 whose use will be better described in 20 decoder 154 are intermediate inverted decoding signals
connection with FIG. 10 in relation to the manipulation
EA and EB. These signals are output in parallel to a
of transceiver 44.
second stage of two decoders 156 which have as addi
The output of PBl of microprocessor 118, which is
tional inputs, control bus signals A0 and A1 correspond
active low, is coupled to an inverter 134 whose output
ing respectively to terminals PAD-1 of microprocessor
136 is a signal, RLY ON, used to power Darlington pair 25 118. Ultimately the ?ve control bits A0-A4 will be
94 in FIG. 5 in order to power up transceiver 44.
converted into twelve key pad signals corresponding to
PA7, PB7, and PB1 are each pulled high through a
the twelve buttons on a telephone key pad correspond
ing to digits 0—9,* and #, and two additional related
radiotelephone signals ON/OFF and volume control,
resistor in the case where the lines ?oat so that decoder
130 and the transceiver power up relay are af?rmatively
maintained disabled unless clearly pulled active low by
an appropriate output on each of these lines.
The outputs of PBO-PB3 of microprocessor 118 are
VOL CONT. Thus, bits A0-A3 represent sixteen possi
ble combinations with a four-bit word which is decoded
in two stages in decoders 154 and 156 and coupled as
the signals, return data transmit,R DATA T; receive
data receive, R DATA R; true data receive, T DATA
sixteen discrete output signals to the inputs of analog
switches 158-164. The A4 bit either disables all sixteen
R and inverted interrupt control, INT-CONT, which 35 outposts or enables the one of sixteen outputs as desig
are speci?c input and output control signals used to
nated by the A0- A3 bits. Consider for example analog
provide necessary control functions for transceiver 44.
switch 164. The four inputs to analog switch 164 corre
spond to the key pad numerals 0-3. With respect to each
of these numerals, two signals will need to be generated
ability to directly respond to and to manipulate a trans 40 in order to command transceiver 44, namely the row
Coupling directly to the input/output ports PBO-PB3
of microprocessor 118 gives the microprocessor the
ceiver if desired. However, in the present embodiment,
and column designations corresponding to key pad
these control ports are not speci?cally used for the
Motorola transceiver illustrated.
numbers 0-3. In particular, numeral 0 is located in the
second column and fourth row. Therefore, the ?rst two
Returning to FIG. 7, output PB1 of microprocessor
outputs of analog switch 164 correspond to column 2,
166, to be described below, is also coupled to an input 45 row 4 and will be activated in response to activation of
/output bus 138. PBl is coupled from input/output bus
one of the inputs to analog switch 164, such as E0. The
138 to an inverter, generally denoted by reference nu
pairs of outputs corresponding to numerals 1, 2 and 3
meral 140. The inverted PBl signal is applied to node
are similarly activated. In the same manner the outputs
142 as the signal, SVC (service) indicating that the
of analog switch 162 correspond to the row and column
transceiver has established radiotelephone contact with
pairs corresponding to key pad numerals 4-7. Analog
a ground station. The signal, SVC, is then coupled to
switch 160 similarly includes as its outputs key pad
one of the inputs of encoder 114 and used as a condi
numerals 8 and 9, * and #. The outputs of analog switch
tional signal to generate the eight bit status words cou
158 are peculiar to radiotelephones, which comprise a
pled from encoder 114 to data bus 116.
?fth row. The ?fth row on a radio telephone corre
The output PB7 of microprocessor 166, to be de
sponds in the second column to the signal END and in
scribed below, is similarly coupled to input/output bus
third column to the signal SND. Included as discrete
138 to an inverter generally denoted by reference nu
signals are the control signals volume, VOL, and
meral 152. Output 154 from inverter 152 is the inverted
power, PWR, which are also referenced in FIG. 9 as
signal,IN USE, which is used to signify that a call has
the input/output signals on bus 138 as VOL CONT and
been placed or is in process. Thus IN USE similarly can
ON/OFF, respectively. Each of the row and column
be used as a conditional signal in decoder 114 to prevent
inappropriate transmission of a status word to data bus
signals from switches 158-164 are active low and are
appropriately buffered and coupled through diodes and
resistors according to conventional principles as illus
Encoder 114 is also coupled to the two highest ad
trated in FIG. 9 to I/O bus 138. By this means micro
dress bits A11 and A12 from address bus 124 through a 65 processor 118 can arbitrarily manipulate and control
series of logic gates, generally denoted by reference
numeral 144. More particularly, A12 is inverted by
inverter 146 and coupled together with address signal
radiotelephone transceiver 44.
Turning now to FIG. 10, a microprocessor 166 run
crystal controlled clock 168, allows signals receive by
transceiver 44 to place signals of the input/output bus
138. Microprocessor 166 interfaces the circuitry and
buses described above with the unique signals used by
processor 166, processor 166 will hold the ?rst data bit '
transceiver 44 and to that extent is transceiver depen
on the R DATA line until T DATA and C DATA lines
returned to the reset state to allow the bit to be read by
the control unit. During a communication initiated by
dent. The signals, return data, R DATA; complemen
enter a data state at which time another bit is sent. At
tary data, C DATA; and true data, T DATA are signals
speci?c to the Motorola transceiver 44 and are digital
signals which are transmitted between transceiver 44
and the controller.
the occurrence of each, idle state, processor 166 will
Each of these signals is coupled through appropriate
logic circuits to input ports of the microprocessor 166.
For example, T DATA, an input signal to microproces
sor 166, is coupled through an exclusive OR gate 170
acting as a buffer since one input is held low. The output
read the R DATA line through gate 176 and compare it
with what is being sent. If there is a con?ict, processor
166 will stop sending and vacate the bus. Processor 166
will request service again when the bus returns to the
idle state.
Consider now the remaining output terminals of mi
croprocessor 166. The outputs PCO-PC2 correspond to
columns 3 through column 1 of the key pad respec
of gate 170, which is T DATA, is also coupled to input 15 tively; outputs PAO-PA4 corresponding to rows 1-5 of
port PB4 of microprocessor 166. C DATA and buffered
the key pad respectively; and signals PB1 or W (ser
T DATA output from gate 170 are provided as the
vice), and PB7 or IN USE described above can be selec
inputs to exclusive 0 gate 172. The output of gate 172 is
tively generated and coupled to input/output bus 138.
thus true whenever T DATA or C DATA are true but
PA7 is a GAIN ADJ signal described below in connec
if in an idle state they both go true, the output is false. 20 tion with FIG. 11 used to adjust audio signal strengths
Thus, the output of gate 172 is true whenever data is
in the voice channel. PC3 is coupled to a push button
being transmitted on the three wire bus and is false
switch which can be manually operated by the call box
when the bus is in the idle state or reset state. The out
user to step up the audio strength of the received voice
put of gate 172 is provided as an input in turn to exclu
sive OR gate 174 whose other input is coupled to an 25 Turn now to FIG. 11 wherein the circuitry illustra
interrupt port PB3 of microprocessor 166. The output
tive of audio processing is illustrated. The microphone
of gate 174 is coupled to the inverted interrupted termi
input of hand set 40 is coupled across terminals 180. The
nal, TNT, of microprocessor 166. This terminal will be
audio signal for the caller is thereby coupled through
active whenever data is being received from the trans
coupling capacitor 182 to an audio ampli?er, generally
ceiver. PB3 port acts as an internal acknowledgement 30 referenced by numeral 184. The output of audio ampli
signal. The output of gate 172 will be low when the data
?er 184 is coupled through coupling capacitor 186 and
link is idle and will be high when it is busy. Therefore
provided as an output at node 188 as the transmitted
when PB3 is high the inverted interrupt, INT, will go
audio, TX AUDIO.
active low when data comes in. This will cause an inter
ON/OFF is a toggle signal on I/O bus 138 as de
rupt to be executed in microprocessor 166 to enable it to 35 scribed in FIG. 7 and is similarly coupled through limit
receive data.
ing resistor 190 to node 188 to override the transmitted
Finally, R DATA is similarly coupled to the output
audio signal according to microprocessor 166 to cause
of transistor 178. Transistor 178 is in turn driven by
output PBD, which is the data output from microproces
sor 166 to transceiver 44. An input of exclusive OR gate
176 is also coupled to the output of transistor 178 and
the transceiver to be turned on or off. Thus, grounding
the on/off line at UQ bus 138 causes the transceiver
power to be turned on if it is off or to be turned off if it
is on.
gate 176 acts as a buffer. Therefore, the output of buffer
Similarly, audio volume control or a gain adjust sig
gate 176 is the signal, R DATA, which is applied to
nal, GAIN ADJ, is provided from I/O bus 138 through
input port PB2 for the purposes of timing.
signal PA7 of microprocessor 166. This is a gain adjust
Consider brie?y the timing protocol used on the 45 signal coupled through transistors 190 and 192 thereby
three wire bus. Normally, the bus is in a reset state, i.e.
biasing node 194 at the input side of audio capacitor 182
C DATA and T DATA are both false. When either one
to a point appropriate with the desired audio gain. Thus,
changes microprocessor 166 will be interrupted. The
the remote central controller can advise call box 10 to
message appearing on the T DATA line contains a bus
turn up the microphone volume as needed through the
direction ?eld, destination address ?eld and data ?eld. 50 manipulation of the T, and C DATA signals coupled to
When microprocessor 166 initiates communication, R
microprocessor 166 which then appropriately generates
DATA data will go low indicating a request from pro
the gain adjust signal, PA7.
cessor 166. A logic unit in the transceiver will establish
Similarly, the received audio from the remote central
bus direction and will expect to receive a message on
operator is coupled to terminal 196. Again, the received
the R DATA line. The message then displayed on R 55 audio signal is coupled through an audio capacitor 196
DATA includes a source address ?eld, destination ?eld
into an audio ampli?er generally denoted as reference
and data ?eld. When the request for service is answered
numeral 200. The feedback of audio ampli?er 200 in
by the transceiver, processor 166 will read the R
turn is controlled through the transistor 202 by means of
DATA line and the destination address ?eld of the
the gain adjust signal, GAIN ADJ, acting through the
incoming message. Processor 166 will place a ?rst bit of 60 output transistor 190. Therefore, the received audio
R DATA on the line at the start of a data state During
communication initiated by the transceiver the ?rst data
gain coupled to input 204 of differential ampli?er 206
can be remotely operator adjusted through gain adjust
bit will appear on the R DATA line after the bus goes
signal GAIN ADJ. The output of differential ampli?er
from the reset state to the data state. The remaining data
206 in turn is coupled to the input of a push/pull ampli
will appear on the R DATA line during the idle state no 65 ?er generally denoted by reference numeral 208. The
data state transition period. The last data bit of the
message will be held on the R DATA line a few micro
seconds after the T DATA and C DATA lines have
output of push/pull ampli?er 208 is coupled as the op
posing input to differential ampli?er 206 thereby main
taining the output 210 of differential ampli?er 206 at a
continual maximum. The output of push/pull ampli?er
completed, the processing again returns to step 210
208 is in turn resistively coupled through audio capaci
where the status is reread.
tor 212 to the receiver or ear piece terminals 214 in hand
set 40.
an inquiry will be made at step 224 as to whether or not
Solar array 34 is also coupled to battery 46 through
controller 42 by means of a shunt regulator. The regula
tor is conventional and thus is not further shown in the
a predetermined time interval has passed. In the illus
trated embodiment call box 10 incorporates a twenty
four-hour ?ag. If a twenty-four-hour interval has not
Figures. Coupling through the shunt regulator prevents
overcharging of battery 46 and thereby eliminates the
potential of any damage due to overvoltages or over
The circuitry now having been generally described in
connection with FIGS. 4-9, turn to the flow diagram of
FIG. 12 which illustrates the basic operation of control
ler 42. Upon power-up as indicted by step 201, a master
reset signal is generated to program control at step 203
to reset all chips within the circuit. This step generates
any logic reset signals required by the microprocessors
If at step 220 an emergency call is not being placed,
expired since step 224 was last queried, the processing
will return to step 211. If on the other hand, twenty-four
hours have elapsed since the last query at step 224, a call
report status routine is entered at step 226. At step 226,
microprocessor 118 will enter a predetermined subpro
gram to telephone the central processing unit regarding
the status of call box 10. Thus, every twenty-four hours
or on any other arbitrary schedule, each call box will
call the central processing center, identify itself and
report its current status or or even a past log of activity.
Many modi?cations or alterations may be made by
118 or 166 or any other logic circuitry. In addition
those having ordinary skill in the art without departing
during this step the transceiver may execute any initial 20 from the spirit and scope of the invention. For example,
protocol operations. For example, in the case of the
the operational routine described at FIG. 10 is illustra
Motorola transceiver of the illustrated embodiment, the
tive only and any other means could be arbitrarily pro
best ground station or forward control channel is se
grammed into execution. It is to be expressly under
lected. Service is then established between the selected
forward control channel and the call box. The trans 25 stood that a different cellular transceiver, such as an
OKI model UM 1043B manufactured by OKI Electric
ceiver or microprocessor 118 then dials a prepro
grammed telephone number and sends identifying codes
which establish the call box’s identity. These numbers
Industries Co. LtD of Atlanta, Ga., could be easily
substituted for the illustrated Motorola transceiver with
appropriate modi?cations to accommodate the substitu
and codes are veri?ed and then communications is se
lectively established on a reverse channel when appro 30 tion according to well know design principles.
priate. All this is protocol which is normally handled by
Furthermore, it should be noted in connection with
the circuit diagrams of FIGS. 4-9 that call box 10 incor
porates a digital address bus, data bus, control bus and
the cellular transceiver and ground station and do not
strictly affect the operation of the invention as de
I/O bus. Therefore, it is entirely within the scope of the
scribed here.
Thereafter, the outputs of each of the status chips are 35 art that such generalized bus structures can be em
set to zero or initialized at step 205. This corresponds to
ployed with other digital circuitry to expand the opera
tional capacities of call box 10. For example, a slow scan
video circuit can be appropriately coupled to the buses
of decoder 130 and as described in connection with the
if desired to provide visual information of traffic condi
latches of FIG. 8.
Having cleared and set each of the status latches, 40 tions at selected points. In addition, a data telemetry
input subcircuit can similarly be coupled to the buses of
processor 118 then enters a self-test program to test the
call box 10 to allow, for example, for the transmission of
contents of memory 120 at step 207. Each self-test pro
digital medical data by paramedical emergency teams
gram is checked a predetermined plurality of times at
who may be attending an accident victim near the site
step 209. The test is repeated until it successfully passes
or timeout occurs. Upon successful self-testing of mem 45 of a call box. Such emergency medical data could be
radio-telemetered from the accident site to the nearest
ory 120, processor 118 will then read the various status
call box which would then retransmit to the nearest
signals as step 211 as described in connection with FIG.
the generation of various set signals shown as the output
8. Should the pole down signal, DWN, for example, be
hospital without the necessity of lifting hand set 40 off
the hook or other direct wire coupling to the call box.
active as determined at step 213, processor 118 will then
enter a specialized down routine at step 215 to take 50 The call box could similarly be time share with environ
mental sensing and reporting systems. Virtually any
whatever appropriate remedial action or reporting as is
desired in the case that the call box has been run over or
device which could bene?t from a remote communica
tions device could be easily combined and accommo
otherwise down on the ground.
dated by the open bus structure of the invention. The
After the down routine is completed, or there its pole
down situation, processor 118 then determines at step 55 adaptability of the invention is even further enhanced
when it is realized that interactive digital and voice
216 whether the battery level is low. If the power is
communications is facilitated through call box 10.
low, it enters a power subroutine at step 218 and per
Therefore, the illustrated embodiment must be under
forms any remedial action necessary in response to low
stood as being provided only for the purposes of exam
battery, such as unconditionally disabling the trans
ple and clarity and not as a limitation of the invention as
ceiver 44. Again, after execution of the low power
de?ned in the following claims.
routine or if the power is adequate, microprocessor 118
I claim:
will then inquire at step 220 whether an emergency call
is being placed‘. If an emergency caller is placing a call
1. In an emergency call box system using cellular
telephone technology, the combination comprising:
by lifting hand set 40 off the hook, an emergency call
routine is entered at step 222 wherein transceiver 44 is 65
a ?xed location call box means, comprising:
powered up, a predetermined phone number is dialed or
a cellular transceiver means for transmitting and
transmitted, together with speci?c identifying informa
tion uniquely identifying call box 10. After the call is
receiving data signals and/or voice signals, ac
cording to controllable parameters,
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