Operating instructions

LOCAL OPERATION
3-84
AF Tone Remote
Overview
The AF Tone Remote system is a remote control facility for controlling remote transceivers of
two-way radio systems by sending AF tones over the dedicated fixed voice circuit from the control
point to the transmitter. There are two formats in general use.
The Sequential Tone format sends a Guard Tone of (usually) 2.175 kHz and 40 ms, followed by
a function tone such as 1.950 kHz, 1.850 kHz or 1.750 kHz and of 40 ms duration, followed by a
continuous PTT tone of (usually) 2.175 kHz for the duration of the transmission.
The Single Tone format sends a PTT control tone of (usually) 2.175 kHz to key the transmitter.
This continues for the duration of the transmission.
Function tones of usually 350 ms duration and of frequencies such as 1.950 kHz, 1.850 kHz or
1.750 kHz are sent simultaneously to the PTT tone to trigger specific functions such as change the
transmitter frequency or mute a receiver.
Testing AF Tone Remote systems
The AF Tones Remote test facility is accessed from the Tones soft key menu of the AF Test mode.
It has a versatile range of tone frequency, level and duration so that it can be used to test most AF
Tone Remote systems.
The AF TONES REMOTE screen is shown in Fig. 3-27.
B5895
Fig. 3-27. AF Tone Remote screen
Frequency and Duration setting
Each of the three tone types (Max, Function and Guard) has its parameters set independently. The
Frequency parameters can be set to any value within the AF Generator range of the Service
Monitor. This is 10 Hz to 30 kHz. The Duration parameter can be set to any value within the
Tones output duration of 20 ms to 20s.
The specific Tone Type Frequency and Duration are set by pressing the appropriate Tone Type
soft key, then pressing the [Tone Freq] or [Tone Durat’n] soft key. Use the Data Input keys to
enter the required value.