Product manual

Alert with PA Commands
95
Trunking Grant Debounce time period has expired), the Model 26 thinks a channel has
been granted and it can transmit. If this LED is on and under these conditions, the Model
26 thinks a channel has not been granted and it will not transmit.
If this LED is on, then the Model 26 is receiving a logic low signal on its RX COR+
input. If the communications mode is “Trunking, Chan Grant on Low COR” and the
Model 26 has requested a channel for transmission by grounding its PTT and the
Trunking Grant Debounce time has expired, the Model 26 assumes a channel has been
granted and it can transmit. If this LED is off under these conditions the Model 26 thinks
a channel has not been granted and it will not transmit.
PTT LED
This LED indicates the state of the PTT output signal. When this LED is on the PTT
output signal is grounded. When this LED is off the PTT output signal is at its open
collector state.
If the communication mode of the Model 26 is VOX, COR or Wire Line, then the Model
26 is always transmitting when the PTT LED is on. If the communication mode is
Trunking, then the PTT LED being on indicates the Model 26 has requested a channel
and may (or may not, subject to channel grant) be transmitting.
Alert with PA Commands
The “Alert with PA” command is one of the most important and complex commands that
can be sent to a Model 6. This command can be for a single unit, for all units, for a single
station, for multiple stations, or for all stations. It is sent by pressing one or more “Alert”
buttons on the Model 26 when the dispatcher wants to alert one or more units and or
stations and also wants to make announcements over the alerted station’s PA. There are a
number of important events that happen during the execution of this type command.
As soon as the Model 6 receives one of these commands it turns on the appropriate
“ALERT” LED (or LEDs) on its front panel and the necessary acknowledgments to the
Model 26. When this response is received by the Model 26, the LED pair(s) representing
the alerted station(s) or unit(s) switch to an alert status. Next the Model 6 turns on its
station’s PA system and starts generating any alert tones programmed for the type of alert
it just received (refer to the Model 6 Station Transponder Product Manual, Part No. 025-
9157).
Once the Model 6 has finished the alert tones, it sends another change of status message
to the Model 26 indicating that its PA is now on. When the Model 26 receives this change
of status it updates the appropriate LED pair to indicate the PA is ready. Since the PA On