MicroComm DXI - Harding Instruments

MicroComm DXI - Harding Instruments
MicroComm DXI
INSTALLATION
INSTRUCTIONS
MAI-425 Master Audio Interface
1.
Intent & Scope
This document describes the installation procedure for the MAI-425 Master Audio Interface. The earliest version
of the MAI-425 (MAI-425-x) had model numbers MAI-425-1 or MAI-425-2 i.e. MAI-425 with a single option. The
second version of the MAI-425 (MAI-425-AB) has model numbers MAI-425-11, MAI-425-21, MAI 425-10 or MAI425-20 i.e. MAI-425 with two option numbers. This document describes the installation procedures for both
versions.
2.
Description
The MAI-425 Master Audio Interface connects to the DXI system via a SAB-400, SAB-401 or SAB-300 Station
Audio Board. The MAI-425 provides an audio communications channel from a master station to a DXI exchange.
The MAI is usually used in conjunction with other devices, such as touch screen monitors or switch panels, which
can provide display as well as control inputs to the DXI system
The MAI-425 provides interface connectors for; a telephone handset, hookswitch, speaker, microphone, and
headset and phantom powered microphone. A combination of these audio devices can be used. If more than one
audio/input device is connected to the MAI the hookswitch and speaker/headset switch will determine which
speaker receives audio and which microphone is active. If the hookswitch is off hook the speaker audio is
connected to the handset speaker and handset microphone audio is connected to the microphone audio lines. If
the hookswitch is on hook the speaker audio is connected to either the headset or handsfree speaker depending
on the state of the speaker/headset switch. If the speaker/headset switch is closed (corresponding to having a
headset jack plugged in) the headset microphone is active and the speaker audio is connected to the headset. If
the hookswitch is on hook and the speaker/headset switch is open then handsfree operation is possible with
either an electret or phantom powered microphone. The following table summarizes the operation of the
hookswitch and speaker/headset switch.
HOOKSWITCH
SPEAKER/HEADSET
SWITCH
CLOSED
OPEN
ON
HOOK
OFF
HOOK
HEADSET
HANDSET
HANDS
FREE
HANDSET
The MAI-425 has provisions for several press-to-talk (PTT) inputs. The PTT switches can be used to control the
audio direction of half duplex calls. The PTT inputs appear on the main DB-25 connector, the handset connector,
and the headset connector. As well the keypad of the IMS-130 has a PTT switch. Although all inputs are in
parallel, and perform the same function, the additional PTT inputs simplify interfacing wiring. For example a PTT
Document IM-MAI-425-2.8
1997 Harding Instruments - Printed in Canada
MAI-425 Master Audio Interface
switch can be located in the handset, on a graphics panel, or a footswitch. If more than one type of PTT switch is
used a switch closure on any one of the switches will cause the MAI-425 to transmit audio to the device being
called.
The MAI-425 provides a pair of contacts on the hookswitch connector that can be used for attaching a
microphone-muting switch. As well the keypad of the IMS-130 has a Mute switch. If the muting switch is closed
all of the microphone inputs connected to the MAI are muted. This feature ensures that the operator can control
the audio that is transmitted over an open audio circuit.
The MAI-425-AB can be used with either a mechanical or magnetic hookswitch, whereas the MAI-425-A can only
be used with a mechanical hookswitch.
3.
Wall Mounted MAI-425 Master Audio Interface
The wall mounted MAI-425 provides an intercom channel from audio devices to an exchange. The MAI-425 is
typically mounted under or inside a control console. Either #8 or #10 round head screws can be used to mount
the MAI
Wall Mounted MAI-425
Page 2
Document IM-MAI-425-2.8
MAI-425 Master Audio Interface
1
1
9.00"
6.00"
Handset
13
25
Hookswitch
1
1
14
Headset
1
I /O Connector
SPKR / MIC
Fuse
Slow Blow
1 A Max
Phantom
Powered
MIC
1
ON
MicroComm DXI
Master Audio Interface
MAI - 425
6.00"
1.80"
6.50"
MAI Base Plate Showing Mounting Hole Detail
Electrical Connections to DB-25 Connector
Electrical connections to the MAI are made with a single DB-25 connector. The MAI has a male connector and the
mating cable requires a female DB-25 connector.
1
13
14
25
Male DB-25 Connector
1
13
25
14
Female DB-25 Connector
The interface module I/O port requires a female DB-25 mating connector with the following pin configuration:
Document IM-MAI-425-2.8
Page 3
MAI-425 Master Audio Interface
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
Signal
Main V +
Main V - (Gnd)
Network B +
Earth Ground
Speaker +
Microphone +
N/C
N/C
N/C
Earth Ground
N/C
Backup V - (Gnd)
Backup V +
Pin
14
15
16
17
18
19
20
21
22
23
24
25
Signal
Main V +
Main V- (Gnd)
Network B Speaker Microphone Push to Talk Input.
N/C
N/C
N/C
N/C
Backup V - (Gnd)
Backup V +
DB-25 Pin Signals
The MAI-425 can be ordered for either +12 Vdc or +24 Vdc operation. For a MAI-425-1 (MAI-425-1B) the main
power should be connected to a +12 Vdc power supply, while a MAI-425-2 (MAI-425-2B) requires a main power
supply of +24 Vdc. For a 12 Vdc ±10% power supply the maximum distance that the power supply can be located
from the MAI-425 is 300 feet (90 meters) using a single 22 gauge pair of wires to connect the power supply. For
the 24 Vdc ±10% power supply, and a single 22 gauge pair wire feed, the maximum distance is 750 feet (230
meters). The dc supply can be connected to pins 1 and 2 as well as pins 14 and 15. This allows the supply wires to
be conveniently paralleled to increase the distance the supply can be located away from the MAI.
The pins labeled Backup V+ and Backup V- (Gnd) can be used to connect a redundant power supply. This supply
acts as a standby power source if the main supply fails. The backup supply must be the same voltage as the main
supply.
The Speaker and Microphone audio pairs connect to two SAB audio ports through the cross connect blocks. This
connection is made with two shielded pair cables.
When the MAI-425 is used with the SAB-300 the Speaker pair is connected to the SAB Audio 16 port and the
Microphone pair is connected to the SAB Master Audio port. The shields are open at the MAI-425 end and
connected to the shield terminal at the terminal block end. The shields are connected together on pin 48 of the
terminal block when using the Audio 16 and Master Audio pair.
When the MAI-425 is used with the SAB-400 (or SAB-401) the Speaker pair can be connected to the SAB Audio 16
pair and the Microphone pair connected to the SAB Mic pair. Again the shields are tied together on pin 48 of the
terminal block. With the SAB-400 (SAB-401) the MAI-425 audio lines can also be connected to two adjacent Audio
pairs (2-3, 4-5, 6-7, 8-9, 10-11, 12-13, or 14-15), with the Speaker pair connected to the even number SAB-400 (SAB401) Audio ports, the Microphone pair connected to the odd number SAB-400 (SAB-401) Audio ports, and the
shields connected to the individual shield terminals.
The Push to Talk (PTT) input is referenced to V- (Gnd) (as are the other PTT inputs), i.e. a PTT switch is connected
between the PTT input and V- (Gnd). The Main V- and Backup V- are connected inside the MAI-425.
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Document IM-MAI-425-2.8
MAI-425 Master Audio Interface
Hookswitch Connections
If the telephone hookswitch is used, it is wired to the interface module via an 8-pin MTA-100-08 female connector
that plugs into a header labeled “Hookswitch”. The hookswitch connections depend on the model of the MAI-425
that you have. We will refer to the two different models as MAI-425-A and MAI-425-A1.
Hookswitch Connections for Model MAI-425-A
The following table gives the connections for a hookswitch to a MAI-425-A. This connector also provides two
terminals that can be used to connect an external switch that allows all microphones to be muted.
Pin
1
2
3
1
4
51
61
7
8
Signal
Microphone Mute +
Microphone Mute - (Gnd)
NC
Hand set Speaker+. Must connect to pin 5 when hand
set is off-hook.
Speaker+ common. Must connect to pin 4 when handset
is off-hook, pin 6 when handset is on hook.
Headset Speaker+. Must connect to pin 5 when hand set
is on-hook.
Speaker/Hand set. Must connect to pin 8 when hand set
is off hook.
Gnd
Interface Module Hookswitch Connector
1Note
that if a hookswitch is not connected to the unit a jumper should be used to connect pins 5 and 6 to allow normal
headset and hands free switching. If a handset is the only audio device that is going to be used then the hookswitch is not
required. In this case a jumper should be installed between pins 5 and 4. As well a jumper must be installed between pins 7
and 8 to activate the handset microphone. These jumpers imitate the off hook state of the hookswitch.
If a hookswitch is required the following schematic shows the necessary field wiring. Harding Instruments
provides Hookswitch Kits HHK-130 or HHK-131 that can be used with the MAI-425-A.
Microphone
Muting Switch
Hook
Switch
OFF HOOK
1
2
3
4
5
6
7
8
MTA-100-08
ON HOOK
Hookswitch Connections for MAI-425-A
Document IM-MAI-425-2.8
Page 5
MAI-425 Master Audio Interface
Connections to the Female MTA Connectors
Most connections to the MAI are made with a female AMP MTA-100 series connector that plugs into the
appropriate header on the MAI. To make the connections shown in the above diagram the mute input connects to
pins 1 and 2 on a female 8-pin AMP MTA-100 series connector that plugs onto the header labeled “Hookswitch”.
To make these connections you should use an AMP Handle Assy 58074-1 tool with a 58246-1 head. The cable
should be cut to length and the outer jacket should be trimmed back about 1/2 inch.
To insert the signal wires into the connector you remove the white cover from the connector, insert the connector
into the tool from the left side (it will travel through the tool in the direction indicated by the arrow), pull the
trigger once to load the connector. Then insert the signal wire for pin 1 (only if you are connecting a muting
switch) into the hole on the top of the tool and pull the trigger to insert the wire into the connector. If a wire is not
required for a pin just pull the trigger to advance to the next position. Then repeat to install the other signal wires
(do not strip the wires). Finally, remove the connector from the tool, replace the cover, and then slide the
connector onto the header pins on the MAI.
Hookswitch Connections for MIA-425-A1
This version of the MAI-425 can be configured to operate with either a mechanical or magnetic hookswitch. Two
versions of the magnetic hookswitch kits are available; HHK-132 and HHK-133 The difference between the two is
that in the “on hook” position the HHK-133 switch is normally open (the same as the mechanical hookswitch)
while the “on hook” position of the HHK-132 is normally closed. The position of a jumper on the printed circuit
board allows for the two possible hookswitch configurations. The hookswitch connections for a mechanical
hookswitch are shown below. When the “on hook” switch position is normally open a shorting jumper should be
placed across the two pins of the 2-pin header CN19, while the pins of CN18 remains open. (The jumper is located
in this position when parts are shipped from Harding Instruments).
Microphone
Muting Switch
Hook
Switch
OFF HOOK
1
2
3
4
5
6
7
8
MTA-100-08
ON HOOK
Hookswitch Connections for Mechanical Switch (MAI-425-A1)
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Document IM-MAI-425-2.8
MAI-425 Master Audio Interface
The hookswitch connections for the magnetic hookswitch HHK-133 is shown below. Again the shorting jumper is
placed across the two pins of header CN19, while CN18 remains open.
Microphone
Muting Switch
Hook
Switch
1
2
3
4
5
6
7
8
OFF HOOK
MTA-100-08
ON HOOK
HHK-133 Hookswitch Connections for Magnetic Switch (MAI-425-A1)
The hookswitch connections for the magnetic hookswitch associated with HHK-132 are shown below. When the
“on hook” position is normally closed the shorting jumper is placed across CN18, and the CN19 pins remain
open.
Microphone
Muting Switch
1
2
3
4
5
6
7
8
MTA-100-08
Magnetic Hook
Switch
OFF HOOK
ON HOOK
HHK-132 Hookswitch Connections for Magnetic Switch (MAI-425-A1)
Document IM-MAI-425-2.8
Page 7
MAI-425 Master Audio Interface
To change the jumper position between CN18 and CN19
you will have to remove the top cover of the MAI-425. The
PC06482-04
printed circuit board is attached to the top cover by
standoffs and a simplified view of the printed circuit
board appears as shown in the following diagram. The
CN19
CN18
on the diagram. The printed circuit board used for the
1
location of the two connectors CN18 and CN19 is shown
MAI-425-AB is identified by the designation PC06482-04.
Harding Instruments provides mechanical Hookswitch
Kits HHK-130 and HHK-131 as well as magnetic
Hookswitch kits HHK-132 and HHK-133 that can be used
with the MAI-425-A1 The following table summarizes the
jumper positions for the various types of hookswitch kits.
Type of
Hookswitch
Jumper
CN18
Jumper
CN19
HHK-130
HHK-131
HHK-132
HHK-133
NO
NO
YES
NO
YES
YES
NO
YES
CN18
CN18
CN19
CN19
(a)
Location of CN18 and CN19
(b)
Jumper Positions (a)CN18 open, CN19 shorted
(b)CN19 open, CN18 shorted
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Document IM-MAI-425-2.8
MAI-425 Master Audio Interface
Handset Connections
The telephone handset is wired to the interface module terminal block according to the following table:
Pin
1
2
3
4
5
6
Signal
Speaker +
Speaker - (Gnd)
PTT switch +
PTT switch - (Gnd)
Microphone +
Microphone - (Gnd)
Interface Module Handset Connector
The telephone hand set must have an electret (or condenser) microphone. Connect the speaker (or receiver) wires
to pins 1 and 2, and the Microphone (or transmitter) wires to pins 5 and 6. The PTT switch is connected to pins 4
and 5. Note the speaker connections are not polarity sensitive, however the electret microphone connections are
polarity sensitive and must have the correct polarity connection for proper operation.
Headset Connections
The headset with boom microphone connects via an 8-pin MTA-100-08 connector as per the following table:
Pin
1
2
3
4
5
6
7
Signal
Speaker +
Speaker - (Gnd)
PTT switch +
PTT switch - (Gnd)
Microphone +
Microphone - (Gnd)
Speaker/Headset - Should connect to pin 8
when headset is plugged in.
Gnd
8
Interface Module Headset Connector
If the headset is always used then a jumper can be used to connect pins 7 and 8. If the headset is used occasionally
then a contact (between pins 7 and 8) is required to activate the headset. This can be an auxiliary contact on the
headset jack, a pair of shorted pins on the headset plug, or a manual switch. Harding Instruments provides a
Headset HEA-110 with a 6-pin plug that can be used with the MAI-425. Only a headset with an electret (or
condenser) microphone should be used
Document IM-MAI-425-2.8
Page 9
MAI-425 Master Audio Interface
Speaker/Microphone Connections
For hands free operation speaker and electret (or c0ndenser) microphone connections are made through a 4-pin
MTA-100 connector according to following table:
Pin
1
2
3
4
Signal
Speaker +
Speaker Microphone - (Gnd)
Microphone +
Interface Module Speaker/Microphone Connector
Harding Instruments provides a Speaker/Microphone Kit SMK-130 that includes a loudspeaker and microphone
mounted on a baffle plate. It is intended to mount behind a console or panel faceplate. See the IM-SMK-130
Installation Bulletins for further details.
Note: Only an electret microphone should be used. Do not use a dynamic microphone.
Phantom Powered Microphone Connections
A phantom powered microphone may be connected to the interface module as given by the following table. The
phantom powered microphone must operate on a 12 Vdc supply. A panel microphone and/or a phantom
microphone can be used with the MAI-425. 420. With the MAI-420 only the microphone on the spkr/mic
connector or the phantom mic connector can be used (but not both).
Pin
1
2
3
4
Signal
Phantom Mic +
Phantom Mic Gnd
Gnd
Interface Module Phantom Powered Microphone Connector
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Document IM-MAI-425-2.8
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