Codan Radio P25 Training Guide - Manual (Page 72)

TRAINING GUIDE | P25 RADIO SYSTEMS
Chapter 5: Conventional Fixed Station Interface Page 64
Figure 5-1 shows a P25 radio system with Conventional Fixed Station Interface. The fi xed stations can
be analog only, digital only or mixed mode stations. Regardless of the RF mode of operation, the fi xed
stations can use either the DFSI or AFSI. A digital only or mixed mode fi xed station will have some
limitations in transporting digital information (NAC, TGID, Emergency, etc.) back to the host over an
AFSI.
Figure 5-1: Conventional Fixed Station Interface Overview
The AFSI and DFSI both support:
1) An intercom capability between the fi xed station and the host without RF transmission.
2) Two different repeat modes. The fi xed station can repeat the incoming signal directly from the
receiver to the transmitter, or if the audio connection from the fi xed station to the host is full
duplex, the host may repeat the incoming audio back to the fi xed station for transmission. If
the fi xed station repeats the signal, any transmission from the host would override the repeat
transmission (except in an AFSI 2 wire simplex tone remote interface).
FIXED STATION
REPEATER
FIXED STATION
SUBSCRIBER
RADIO
Um
Common Air Interface
(CAI)
Ef
Fixed Station Interface
(FSI)
RF
SUB-SYSTEM
RFSS
CONSOLE
SUB-SYSTEM
Ec
Console
Sub-System
Interface
(CSSI)
Analog (AFSI)
Digital (DFSI)
FIXED STATION
FIXED STATION
SUBSCRIBER
RADIO
Analog (AFSI)
Digital (DFSI)
Analog (FM) or
Digital (C4FM)
Analog (FM) or
Digital (C4FM)
Fixed Stations can be
Analog, Digital or Mixed Mode Host