CP-300 & TW-12

Belt-Pack & Interface

Two-Wire System

INSTRUCTION

and

SERVICE MANUAL

CA)

ClearCor®e

Intercom systems

1111 17th Street * San Francisco, California 94107 * 415-861-6666

CLEAR-COM 810044 TW/10-84 REV B

CLEAR-COM CP-300 BELTPACK STATION

& TW-12 TWO-WIRE INTERFACE UNIT

OPERATION & SERVICE MANUAL

Contents

Page #

Introduction to the Belt-Pack

& Interface...I

Headsets

Interconnect Cable

CP-300 in a Single-Channel System

CP-300 in a Two-Channel System

TW-12 Set-Up

Loop-Through Interconnection

Specifications ..........

6

7

8

Illustrations

Figure 1: System Interconnection

Figure 2: CP-300 Belt-Pack ................. 4

Figure 3: TW-12 Interface

........................... 11

CLEAR-CON CP-300 BELT-PACK

Operation & Service Manual

ADDENDA

CP-300 "Call" Signalling

(replaces "Optional Signalling" section of Introduction to the

Belt-Pack; page 1, column 2)

The signalling option for the CP-300 provides a visual alert for users who aren't listening to the intercom. Pressing the CP-

300's CALL button sends a special call-signalling voltage (either a 20 kHz tone or a positive DC voltage) onto the intercom channel currently in use. This voltage is detected by all other stations which are switched to that channel, causing their call lights to turn on.

The 2-channel/1-channel mode-select switch sets the signalling method: a tone for 2-channel or "TWi operation, or DC voltage for single channel (standard Clear-Com) use.

The signalling option requires installation of a switch/light button and an additional PC assembly.

Headsets

(see System Installation, page 3)

The headset used with the CP-300 should have a rated mic output level of -55 dBv.

CP-300 as a two-wire /two-channel station

(see System Installation, page 4)

Using the CP-300 as a two-channel station requires connection to a TW-12 Interface Unit OR connection to an existing "TW' (twowire) two-channel intercom system. The CP-300's side panel contains a recessed "mode-select" switch, which must be set to the

"2-CH MODE" position (refer to Figure 2 for switch location).

CLEAR-COM 810044 TW/5-85 REV B

CLEAR-COM CP-300 BELT-PACK STATION & TW-12 INTERFACE UNIT

OPERATION MANUAL

.

1. INTRODUCTION TO THE BELT-PACK & INTERFACE

The Clear-Com CP-300 is a portable belt-pack intercom that allows com- munication on two channels, using standard two-conductor microphone cable. The CP-300 is different from other Clear-Com Stations be- cause it requires connection to an interface unit, Model TW-12, to utilize its full capabilities.

channel-selection (A or B), a three-position mic switch (on/off/ momentary on), and a low-profile volume control. The controls are different sizes to facilitate adjustment by touch only. Al I controls are protected by the raised lip of the belt-pack's chassis.

When the CP-300 is used in its two- channel/two-wire mode, two audio channels are transmitted on one cable: channel A audio and DC power on one of the wires, channel B audio on the other wire. The System must include the TW-12 Inter- face when two intercom channels are required on one cable. (Clear-Com typically uses one cable to support one audio channel plus power, or it uses multi-pair cable for two or O more channels.)

The CP-300 features Clear-Com's excellent speech intelligibility in all high- and low-noise environ- ments. It also includes a mic limiter, which holds the output relatively constant over a 30 dB input range. The CP-300 has the same pin-to-pin connections and functions as RTS intercoms (e.g.,

RTS Model BP-300), with better performance.

Optional Signalling

The Visual Signalling function, a typical Clear-Com feature, is figured differently in the CP-300 than it is in standard Clear-Com

Stations.

The CP-300 uses a 20,000 Hz signal, transmitting it on the audio channel selected for communicating (A or B). This signal is detected by the other CP-300's which are using that same channel (A or B), causing the CP-300 call lamps to light up.

When the signalling option is included in the CP-300, a call lamp/ button is added to the belt-pack's chassis. The system of signalling is determined by the one-channel/ two-channel mode switch on the CP-

300 operation; it switches the signallirg circuitry from DC mode

(standard Clear-Com) to the 20k Hz signal used in the 'TW" system.

A unique CP-300 feature is its switch-selectable operation as a two-channel/two-wire station or as a "standard" one-channel Clear-Con station. It operates in a stand- alone, two-channel system or com- bined in a system with standard

Clear-Com Stations. Refer to the system diagrams, page 3.

The CP-300's headset amplifier provides power to drive a standard

Clear-Com headset to levels greater than 110 dB SPL, without any distortion. The belt-pack operates with either a dynamic or a carbon headset, providing an input connector for each one.

Other CP-300 features include its

"user-friendly" control lay-out, including the rocker switch for

The CP-300 also incorporates "automatic headset detection," which mutes the mic pre-amp when the headset is not plugged in. Therefore an unused yet on-line beltpack doesn't cause background noise.

(continued)

2

CP-300 and TW-12 Description, continued

The belt-pack provides a sidetone adjustment, which allows the user to vary the level of his/her voice

(full on to 25 dB null) as heard in the headset. This control need be set just once, if at all, even if other intercom stations join or leave the intercom network.

TW-12

The TW-12 Interface connects be- tween the CP-300 Belt-Pack(s) and a standard Clear-Com Power Supply or

Main Station. Its function is to translate audio line levels and call signal I ng, and to modulate one of the two audio channels onto the DC power line. The TW-12, which is in a space-saving rack- mount chassis (1.75" high), con- tains no operational controls ex- cept for a Mode-Select toggle switch.

The TW-12* translates levels and voltages from two separate Clear-

Com channels, and provides the two- wire, two-channel output on mic cable. An auto-termination feature prevents oscillation in partially- connected systems. The TW-12, which typically receives its power through the connection to Clear-

Com, translates the visual call signalling between the two systems

(tone to DC & vice versa).

The TW-12 can also be used to link the Clear-Com System with a twowire, two-channel intercom system

(e.g. RTS's "TW" System). The

Interface supports RTS BP-300 beltpacks as well as Clear-Com's CP-300 belt-packs.

When the TW-12 is used to link a

Clear-Com System with a two-wire two-channel system, the number of intercom stations that may be contained within both systems is only limited by the capacity of the power supplies in the respective systems.

The ability of the TW-12 to support intercom stations is only limited when it functions as support for a stand-alone two-wire, two-channel system. The TW-12 supports up to ten (10) two-channel/two-wire in-

,tercom stations with signal ling or up to 16 such intercoms without the signalling function (Clear-Com CP-

300, RTS BP-300, or equivalent).

The TW-12, once set up, is transparent to the intercom users. Its one control is a toggle switch that selects between internal termination (for "TW" belt-packs) or external termination (for interfacing with an RTS-type power supply).

0

W

II. SYSTEM INSTALLATION

Headsets

The CP-300's dynamic headset input is a 4-pin, male XLR.

To insure proper level and performance, the dynamic headset

(or handset) should have the following characteristics--

Mic Impedance:

Mic Output Level:

150-250 ohms

-55 dB

Ear Element Impedance: 50-2000 ohms

The dynamic headset connector pin-out is:

Pin 1: mic common

Pin 2:

Pin 3:

Pin 4: mic hot headphone common headphone hot

NOTE: Do NOT connect headphone ground and mic ground together at any point.

The CP-300 also accepts a standard carbon mic headset, and provides a 1/4" phone jack for the input. The carbon headset should contain a 50 ohm carbon-type microphone, a 600-1000 ohm earpiece, and the cord should be terminated in a 1/4",

3-conductor (ring/tip/sleeve) phone plug.

The carbon headset connections are:

Tip: mic hot

Ring: headphone hot

Sleeve: ground

Interconnect Cable

Use standard 2-conductor microphone cable to interconnect the

CP-300 with other belt-packs or the TW-12. You can use unshielded cable where AC interference is not a problem.

We recommend rubber-insulated and jacketed cable, such as:

Belden 8413 or equivalent (24 ga., stranded conductors) for lines running up to 500 feet in length;

Belden 8412 or equivalent (20 ga., stranded conductors) for lines running 500-5000 feet in length;

Belden 8428 or equivalent (18 ga., low-capacity) for lines greater than 5000 feet in length.

FIGURE 1: System Interconnection

CS-210 TW-12 A 13

CP-300's in 2-CHrmode

(loop-through)

TO

RM-120A KB-112

P-Box

RS-10A lA

B

TO

3 CLEAR-COM

Typical mixed standard and 'TW" two-channel system (portable)

3

SYSTEM INSTALLATION, continued

The CP-300 as a Single-Channel Station

First be sure that the recessed two-position switch on the belt-pack's side is set to the "SINGLE CH MODE (select B)" position (see Figure 1 for location of mode-select switch).

Second, the CP-300 operator must communicate on Channel B when using the single-channel mode; be sure that the CP-300

Bring mic cable from the Clear-Com Main Station or Power

Supply and plug it into the D3F connector labelled "input" on the CP-300. The pin-out is--

Pin 1: Common

Pin 2: +VDC

Pin 3: Intercom Audio

After completing all connections, plug in the headset and turn up the volume. The Station is now ready to operate.

The CP-300 as A Two-Wire/Two-Channel Station

This mode requires the TW-12 to support the CP-300. First be sure that the CP-300 mode-select switch is set to the "2-CHl

MODE" position (see Figure I for location). In the pin-out assignment for the CP-300 input and extension connectors is--

Pin 1: Common

Pin 2: +VDC and Channel A Audio

Pin 3: Channel B Audio

The INPUT to the CP-300 MUST come from the TW-12 output connector (3-pin male XLR) labelled "System Interface."

In this mode, the TW-12 must be connected to two standard

Clear-Com channels via the interface's two input connectors, one for Clear-Com channel A and one for Clear-Com channel B.

After completing all connections, plug in the headset and turn up the volume. The Station is now ready to operate.

(9347

I t

Figure 2: CP-300 Belt-Pack

4

SYSTEM INSTALLATION, continued

TW-12 Set-Up

The TW-12 provides two male and two female 3-pin, XLR connedtors for input and extension of Clear-Com channels A and B, plus a third set of XLR connectors for use with the twochannel/two-wire end of the system. For all connections, use standard two-conductor shielded mic cable. See Figure 3.

The TW-12 rear panel pin-out assignments are:

Clear-Com System Connectors:

Pin 1: Common

Pin 2: +VDC

Pin 3: Intercom Audio (Ch A or B)

System Interface Connectors:

Pin 1: Common

Pin 2: +VDC and Ch A Audio

Pin 3: Ch B Audio

The TW-12, once set up, is transparent to the user. It has only one control on the front panel: a toggle switch that selects between the internal or external termination mode.

Set this switch to the "2-Channel Station" position to support TW-type belt-packs (internal termination); or set it to the "System Interface" position for interfacing the Clear-Com

System with a TW-type system that includes its own power supply (external termination).

CP-300 Loop-Through Interconnection

Regardless of its operation mode, the CP-300 has a 3-pin male connector labelled "extension" to provide an internal loop0 through. This allows you to daisy-chain CP-300's or similar stations along one stretch of cable. All stations using the loop-through MUST be in the same operation mode (one channel or two-channel).

NOTE: To prevent shock hazard, ground loops, and noises, NEVER connect Pin 1

(common) directly to the station chassis. In addition, never connect Pin 1 to the shell of the mic cable.

T__/F~r

45

(t',5 /,

0

Figure 3: TW-12 Interface

(402 60)

sfUea_

K~~~~~~~~~~~~~

5

111. CP-300 OPERATING CONTROLS

The MIC SWITCH turns the headset mic ON and OFF, and includes a third position marked "on (mom)"

(momentary on) for quick messages.

The CHANNEL-SELECT SWITCH allows:

1) communication on Channel A or on

Channel B, when the CP-300 uses the 2-Channel mode, OR

2) communication on one channel (3) when the CP-300 uses the Single-

Channel mode.

Note that the Channel-Select Switch must be set to "B" when the CP-300 operator is using the standard

Clear-Corn single-channel mode.

The VOLUME knob adjusts the audio level in your earphone(s).

The SIDETONE adjustment is located on the side of the belt-pack, and is used to vary the amount of your voice as heard in your headset.

It does not affect the level of inco- ming or outgoing signals, and is set at the factory to be approxi- mately 6 dB lower than incoming signals. To re-set it, locate the unmarked hole (which contains a trimpot). Plug in your headset, insert a small-bladed screwdriver through the hole, and engage the slot on the trirnpot. Turn up the headset volume all the way, and start talking to yourself while slowly turning the screwdriver.

A null point will be found where you can barely hear yourself; the normal setting is anywhere to the left of the null.

The optional VISUAL CALL SIGNALLING function follows the setting of the belt-pack's Channel-Select switch; for instance, if you are talking on channel A, pressing the Call switch will illuminate the lights at all other Stations communicating on channel A. Call lights will stay on for as long as the switch is depressed. The CALL LIGHT lights up to attract your attention when another Station operator (using the same channel) activates the Call signal.

6

IV. PARTS LISTING

CP-300 Belt-Pack Without Signal Option part #

150048

210002

210003

210013

210050

240031

250041

250233

250234

640007

710152 description capacitor, lOOpF 1kv 20% RF input connector, 3-pin female XLR output connector, 3-pin male XLR volume control knob large belt-clip

CP-300 chassis

CP-300 chassis cover qty.

1

1

1 dynamic headset input, 4-pin male XLR 1 carbon headset input, 1/4" phone jack 1

1

1

1

1 hole plug 1

CP-300 printed circuit board assembly I

CP-300 Belt-Pack With Signal Option same as above EXCEPT: delete part #640007, hole plug and add:

510064 Call switch with lamp 1

710153 CP-300 signalling circuit board assy. I

210002

210003

240017

250073

250152

250231

250232

510006

710147

TW-12 Two-Wire Interface input connector, 3-pin female XLR output connector, 3-pin male XLR rack handles for 1.75' chassis

1.75" mainframe chassis mainframe chassis cover two-wire interface front panel two-wire interface rear panel mini-toggle switch, 2-position two-wire interface printed circuit asy.1

1

1

3

3

2

1

1

1

7

V. CP-300 SPECIFICATIONS

AMPLIFIER DESIGN: Solid-state, low-noise I.C. amps; current-limited and shortcircuit-protected, with reverse polarity protection.

MICROPHONE PRE-AMPLIFIER

Mic Input Impedance:

Mic Pre-amp Gain: 50 dB

Max Input Before Clipping: -32 dB

Freq. Response:

Carbon Mic Current: 10 ma nominal

Limiter Range:

250-12k Hz, *5dB output for 30 dB change in input

HEADPHONE AMPLIFIER

Load Impedance Range:

Output Level:

1k ohm

8 dB change in

50-2k ohms

+15 dBm into

300 ohm load

Headset Level:

(with dynamic Clear-Com headset)

Distortion: <0.1% THD 6 I kHz

Amplifier Gain:

Freq. Response:

>110 dB SPL

24 dB

150-12k Hz, 42dB

GENERAL

Station Bridging

Impedance: >20k ohms (200-10k Hz)

Avg. Line Level: -6 dB, +3 dB max

Sidetone Adjust: 25 dB null-full on

Call Light

Sensitivity: (receive) 4 volts DC

(send) IlVDC

Power

Requirements:

DC Voltage Range:

25 ma quiescent

12-32v @ 25ma average, 25v nominal

Max. Number of CP-300s with TW-12: without signalling, 16 with signalling, 10

CONNECTORS

Headset:

Line:

& (1) 1/4", 3-cond. phone jack

- two 3-pin XLR, I male and 1 female for loop-through

PHYSICAL CHARACTERISTICS

Dimensions: 3.78" x 5.1" x 1.6"

Weight: 14.5 oz

(without signal circuit)

Ambient Operating

Temperature: 0-60 C (32-1400 F)

Humidity: 0-90% relative humidity

VI. TW-12 SPECIFICATIONS

LINE CHARACTERISTICS, CLEAR-COM SIDE

Level: -15 dBv nominal, 0 dBv max before clipping

Impedance: 200 ohm AC termination

5000 ohm DC termination

LINE CHARACTERISTICS, TW SIDE

Level: -5 dBv nominal, +3dBv max

Impedance: 200 ohm AC

GENERAL CHARACTERISTICS

Gain, Clear-Com-to-TW: +12 dB

Gain, TW-to-Clear-Com: -12 dB

Freq. Response: 200-10k Hz, 13 dB

Power Requirements: 12-32 VDC, 50ma quiescent plus current for TW side

TW Power Capacity: 500ma max

(6-12 stations)

SIGNALLING, TW SIDE

Frequency:

Freq. Tolerance:

Tone Level:

DIMENSIONS

20k Hz

;100 Hz send,

+500 Hz receive

-6dBv minimum send,

-30dBv maximum receive

SIGNALLING, CLEAR-COM SIDE

4 VDC maximum receive,

11 VDC minimum send

1.75" H x 19" W x 6" D

44mm H x 483mm W x 152mm D

0 dBv is referenced to 0.775 volts RMS

8

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