Motorola PM1200 User Manual page 30

Radio Firmware Features
The receiving radio will mute its speaker before loss of a carrier is
detected, upon receiving the TPL reverse burst.
If the TPL Reverse Burst is programmed to None (disabled) via the
CPS, then the TPL reverse burst will not be transmitted at the end,
upon the PTT button release. If the TPL shut-off code is not
transmitted, then the receiving radio will not mute its speaker before
loss of a carrier is detected, unwanted noise (squelch tail) during loss
of carrier detection will be heard.
Table 2 shows the result of squelch tail elimination on the receiving
radio based on the TPL reverse burst setting on transmit and receive
radio.
TPL Tx Reverse Burst Setting
TPL Tx Reverse Burst
on Transmitting Radio
Standard
Non-Standard
When Reverse Burst is enabled in the CPS, the TPL Reverse Burst
that is transmitted at the end of the transmission changes the phase
prior to the removal of the carrier to eliminate the squelch tail.
There are 2 formats in use:
- Advances the phase of the tone 240 degree forward
- Advances the phase of the tone 180 degree forward
This setting is programmable via the CPS.
18
Table 2: Squelch Tail Elimination Results
TPL Tx Reverse Burst
on Receiving Radio
Non-Standard°
Standard
Squelch Tail
Elimination
Yes
Yes
No