Codan Radio P25 Training Guide - Manual (Page 80)

TRAINING GUIDE | P25 RADIO SYSTEMS
Chapter 6: P25 Trunking Page 72
Figure 6-1: P25 Trunking and Conventional System Overview
IMPLICIT / EXPLICIT
A P25 trunked system can be confi gured in either the implicit mode or the explicit mode of operation.
In the implicit mode of operation, all radios are pre-programmed with the channel and frequency
information. The radio then looks internally to the pre-programmed channels when switching between
control and traffi c channels. The explicit mode sends the channel and transmit or receive frequency
over the air to the radio. The implicit mode of operation typically uses single block messages, where
the explicit mode typically uses multi block messages.
Data
Packet
Trunking
P25 Radio
System
Control
Channel
Traffic
Channels
Trunking
Controller
Conventional
Voice
Message
Confirmed Unconfirmed
Data
Packet
Traffic
Channel
Voice
Message
Confirmed Unconfirmed
Link Control
Word used for
signalling
Link Control
Word used for
signalling
Used for signalling and
broadcast of system information
Packet types are of Trunking
Signaling Block (TSBK) or
Multiple Block Trunking (MBT)
Inbound channel access
based on Slotted ALOHA