GAI-Tronics MRTI 2000 (No. PL1877A) Microprocessor Radio Telephone Interconnect Installation & Service Manual - Manual (Page 147)

PL1877A Microprocessor Radio Telephone Interconnect PL1877A – Radio Installation
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Using the Parameters Modification Procedure in this manual, set the following required parameter
settings:
Parameter Setting
1 0 (de-emphasis)
2 1, JU202 OUT (mid-level source)
3 0 (internal carrier detect)
4 Don’t care
5 0 (internal squelch for carrier detect)
6 0 (No PL detect input required)
1 (PL detect input required)
7 0 (PL detect input is active low)
1 (PL detect input is active high)
9 1 (simplex)
10 0 (active low PTT sense input
70 1 (enhanced VOX simplex mode)
All other parameters are programmed as applicable to system requirements. Refer to the Parameters
Modification Procedure and then the Level Setting sections of this manual.
N OTES :
1. Repeater transmit turn-off delay in repeater control station installations:
When the PL1877A is being installed in a control station controlling a repeater, it is necessary to
ensure that the repeater does not stay on the air after the control station unkeys. If the PL1877A
detects carrier (and PL/DPL, if applicable) after unkeying the control station, it is erroneously seen as
a mobile transmission. In systems that require PL/DPL and retransmit (not generate) the PL/DPL
signal (such as most community repeaters), no problem is encountered since carrier-only is not seen
as a system mobile. Some repeater stations have a jumper for turn-off delay, but many delay turn-off
more than a second even though the “0” position is selected. In these cases, reducing the timing
capacitor to a much smaller value produces the required results (for example, changing C11 on a
MICOR repeater TLN4662A squelch gate module from 68
µF to 4.7 µF).
2. 60-Second Mobile Inactivity Timer:
In the enhanced VOX simplex mode, the landline caller cannot be interrupted by the mobile (until the
30-second time-out). Therefore, it is possible for the mobile to hear the warning ticks and not be able
to reset the inactivity timer because the landline party is talking. Therefore, it is recommended that
the mobile inactivity timer (parameter 122) be set to 3 minutes of mobile inactivity in Enhanced
VOX simplex systems.