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
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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.
4.
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.