FunctionalDescriptions
Receive Call
Individual Selcall Receive Sequence
Operation
i
If Transpond configured the unit transponds
Unit’s Rx Selcall Address is decoded
ii Audio Open; "Open" Alert is output
iii "Call Received" Alert is output; LED output is pulsed
i
Alert beeps stop
Alert cancelled by ’blip’ of PTT, Call
or Quiet/Open buttons, or Time-Out
Conversation takes place; Conversation complete
i Unit "Closed" Alert is output. Radio is Closed.
Radio is muted by: push-button/Timed Mute Reset
/Remote Reset
GROUP Selcall Receive Sequence
i
No transpond can take place for a GROUP-Call
A GROUP-call with the unit’s Rx Selcall
Address is decoded
ii "GROUP-Call" Alert is output; this alert is self cancelling
The calling party transmits the message/s
he CM1481 can only reply to an originator whose Tx Address is
configured, and not to the other GROUP members Conversation complete.
T
-
i Unit "Closed" Alert is output. Radio is Closed.
Radio is Closed by: push-button/Timed Mute Reset
/Remote Reset
Fig.5 Rx Call Operation
Transmit Call
Operation
Normall Selcall Transmit Sequence
i
Unit "Open" Alert is output.
Unmute the radio by push-button operation -
(see Single/DualButton operation)
- or employ ’Muted Call’ initiation Method
ii Radio squelch circuitry released to normal operation
Monitor the channel.
i
"Call Transmitted" Alert is output
Transmit the (Tx Address) Selcall by push-button
operation
Note that if the BUSY input is active, a call
cannot be transmitted (PTT Lockout)
ii Tx ON is active; the Selcall is output at TONE OUT
A
B
If the system is ’No Transpond’, when the called station’s reply is received the converstaion may continue.
If the system is ’Transpond’, await the transpond action then conversation may continue.
i
PTT Timer started
Conversation complete
i Unit "Closed" Alert is output. Radio is Closed.
Start Conversation
Radio is Closed by: push-button/Timed Mute Reset
/Remote Reset
Fig.6 Tx Call Operation
A polarity programmable LED drive output is available if a visual indication of a received
Selcall is required. It is recommended that, under LED conditions, this output is configured
as an “active high” and an external LED is connected directly to GND (0V).
With due regard to the specified current limits, this output may be used to activate mobile
horn-honk/indicator driver circuits.
LED Drive
If the ‘Selcall Received Alert’ has been activated but not cancelled, the module can be
configured so as to leave the LED illuminated as a Call Memory.
The use of any push-button function will cancel this LED action.
LED Call
Memory
Configured as LED Call Memory:
12
CMLMICRO [ CML MICROCIRCUITS ]
