Codan Radio P25 Training Guide - Manual (Page 43)

P25 RADIO SYSTEMS | TRAINING GUIDE
Chapter 3: P25 Technical Information Page 35
CONVENTIONAL CONTROL MESSAGES
The TIA-102 documents defi ne a number of control messages for trunking systems that can be applied
to conventional systems. These control messages use Packet Data Units to transfer information, and
may be optionally implemented by a manufacturer.
The messages are as follows:
Emergency Alarm
Emergency Alarm is activated by a user to inform the dispatcher an emergency situation is encountered.
The Emergency Alarm is typically used in a life threatening situation.
Call Alert
Call Alert sends a data packet to the destination subscriber identifying the source of the Call Alert and
requesting the destination to contact the source. Call Alert is typically used if the destination subscriber
did not respond to a voice message from the source.
Radio Check
Radio Check is used to determine if a specifi c subscriber is currently available on the radio system.
A response to the Radio Check is required, or the system will assume the subscriber is not available.
Radio Inhibit (Radio Uninhibit)
Radio Inhibit is used to deny all calls between the inhibited subscriber and the RFSS. Radio Uninhibit
cancels the inhibit status of the subscriber.
Status Update and Status Request
Status Update is used by a subscriber to indicate its current status (user and unit status) to a designated
target address. Status Request is used by a subscriber to request the current status of a specifi ed
subscriber.
Message
A Message may be sent by a subscriber or the RFSS to send a short message to another subscriber.
Telephone Interconnect Dialing
Telephone Interconnect Dialing will allow a subscriber to initiate a Unit to PSTN call, and will allow a
telephone network to initiate PSTN to Group and PSTN to Unit calls.
Radio Unit Monitor
Radio Unit Monitor is used to cause a subscriber radio to key up when requested to do so by a dispatcher.
Radio Unit Monitor allows a dispatcher to listen to activity at the location of the subscriber.