Tyco Electronics MM23772 - Manual (Page 68)

MM23772, Rev. B
68
signal quality of the control channel for each site in its adjacent scan list. (The signal quality metric used
for the ProScan algorithm is based on a combination of both Received Signal Strength Indicator (RSSI)
and Control Channel Verification (CCV) measurements.) When the selected system degrades to a pre-
programmed level, the radio will begin to look for a better control channel. Once a control channel that
exceeds the pre-programmed parameters is found, the radio will change to the new system and emit a tone
(if enabled through programming). If the control channel is completely lost, the radio will enter Wide
Area System scanning and search the programmed adjacent systems until a suitable control channel is
found.
8.22 EMERGENCY OPERATION
The radio's ability to declare an emergency, clear an emergency, remain locked on an emergency system
and group, and the emergency audio and display freeze can each be enabled or disabled through
programming. When an emergency is declared scanning will stop and restarts only after the emergency
has been cleared.
8.22.1 Receiving an Emergency Call
When receiving an Emergency Call on the selected group and system, an alert beep is heard and is
displayed. The message
*RXEMER*
flashes in the display on line two until the emergency condition is
cleared.
8.22.2 Declaring an Emergency Call
To send an emergency call to a selected system and group (or on an optionally pre-programmed group):
1. Press and hold the red EMERGENCY button that is on top of the radio in front of the antenna for
approximately one second (this time is programmable and therefore could be longer or shorter; check
with the system administrator). The radio will transmit an emergency call request with the radio ID
until an emergency channel assignment is received.
2. When the working channel assignment is received, the radio sounds a single beep indicating the radio
has auto keyed (see Table 8-2) and is ready for voice transmission.
*TXEMER*
flashes on line two in
the display until the emergency is cleared.
3. Press PTT and speak into the microphone in a normal voice. and momentarily turn ON.
4. Release PTT when the transmission is complete.
To clear the emergency first press and hold the  button. While continuing to hold the  button, press
the EMERGENCY button. (This will work if the radio is programmed to clear emergencies.)
8.23 INDIVIDUAL CALLS
8.23.1 Receiving and Responding to an Individual Call
When the radio receives an individual call (a call directed only to the user's radio), it un-mutes on the
assigned working channel and displays . The first line on the display shows the logical ID number of the
unit sending the message, or the associated name if the ID number is found in the individual call list. The
radio can be programmed to ring when an individual call is received. If enabled, the ring begins five
seconds after the caller un-keys and will continue until the PTT button, the  button or the individual
call mode is entered.