Operation, Call originated by a page/party, Or call/talk user to a radio user – GAI-Tronics 1931888-3011 Page/Party to Coupler User Manual

Page 5

Pub. 42004-245B

Model 1931888-3011 Page/Party

to Radio Coupler

Page:

5 of 10

\\s_eng\gtcproddocs\standard ioms - current release\42004 instr. manuals\42004-245b.doc
03/08

Operation

The Model 1931888-3011 Coupler connects one radio frequency (channel) to one party line in the
Page/Party

or Call/Talk system, usually party line 5. When a remote radio is not in use, the coupler

monitors party line 5.

In order for a Page/Party

or Call/Talk user to contact a radio user, the caller must go off-hook on party

line 5. The resulting communication is simplex. This means that the radio user controls the flow of the
conversation with the push-to-talk, release-to-listen mechanism of the radio.

Call Originated by a Page/Party

or Call/Talk User to a Radio User

Audio Path from Page/Party

to Radio

The caller from a Page/Party

or Call/Talk station goes off-hook on the designated party line. This causes

the station’s output transformer to load the line (loop current on the line begins) at the Model 1931888-
3011 coupler’s TB-7 and 8 and is detected by the Model WBA2757 Sensing PCBA inside the coupler.
The following relay functions occur:

1. The sensing PCBA detects the off-hook condition on the party line and activates the

XFR

relay and

illuminates LED 3.

2. The

XFR

(transfer) relay is activated by the sensing PCBA. It transfers the audio path from the

‘Radio-Page’ line to the ‘Radio-Party’ line.

3. The

VOX

board detects audio from the system party line. When sufficient system party line audio is

present, it activates VX1 relay and illuminates LED 1.

VX1

(

VOX

) relay toggle operation is activated by the Voice Operated Switch (

VOX

) PCBA. While the

relay is activated:

• It provides the audio connection path from the party line to the radio’s microphone-in circuit (TB-

12 and 13) via the coupler’s

RADIO VOL

control (

VC1

• It disables

SQ1

(squelch) relay during party line talk mode for uninterrupted communication.

• It provides a contact closure at TB-11 to ground to key the radio transmitter circuitry.