Operating instructions

LOCAL OPERATION
3-75
Tone ON/OFF control
When the RF SEQUENTIAL ENCODER screen or the AF SEQUENTIAL ENCODER screen is
displayed, the sequential tones are turned on or off by the orange [ON/OFF] function key.
If the sequential tones are ON and the Tx TEST, Rx TEST, Dx TEST or AF TEST mode selected,
the tones will continue to be generated.
If the tones out routing has been set to give RF tones, this is provided by modulation generator 1.
The legend
---Tones --- will be displayed against MOD1 FREQ on the RECEIVER TEST or
DUPLEX screens. If MOD1 is selected, the sequential tones can be controlled by repeated presses
of the orange [ON/OFF] function key. If
MOD1 FREQ is selected, the tones are still controlled by
the orange [ON/OFF] function key, but if a frequency is entered using the data keys or if the
variable control is adjusted, the tones will cease. They can then be re-started only when the
RF
SEQUENTIAL ENCODER screen or the AF SEQUENTIAL ENCODER screen is displayed.
If the tones out routing has been set to give AF tones, this is provided by audio generator 1. The
legend
--Tones-- will be displayed against AF1 FREQ on the TRANSMITTER TEST, DUPLEX or
AF TEST screens. If AF1 is selected, the tones can be controlled by repeated presses of the orange
[ON/OFF] function key. If
AF1 FREQ is selected, the tones are still controlled by the [ON/OFF]
key, but if a frequency is entered using the data keys or if the variable control is adjusted, the tones
will cease. It can then be re-started only when the
RF SEQUENTIAL ENCODER screen or the AF
SEQUENTIAL ENCODER screen is displayed.
Testing sequential tone transmitters
To test the operation of transmitters sending sequential tones calling signals, proceed as follows:-
Select the Tx TEST mode, then make all the required settings and RF connections for
conventional transmitter testing. Refer to the Tx TEST section of this manual for the correct
procedures. Set the frequency of the Service Monitor input to that of the transmitter output.
Key the transmitter and check that the Service Monitor is obtaining a signal from the transmitter.
Select TONES mode. The attenuators in the receive path of the Service Monitor will be held at
their current setting. Press the [Sequential] key. The
RF SEQUENTIAL TONES DECODER
screen and menu is displayed. See Fig. 3-23, Sequential tones decoder screen. If the encoder
screen is displayed, press the [Decode] key.
Fig. 3-23 RF Sequential tones decoder screen
Check that the tones standard shown above the tone number/frequency list corresponds to the
system used by the transmitter. If this is not correct, select the correct standard from the menu
accessed through the [New Std] key.
Key the transmitter to transmit a tone sequence. Within the Service Monitor the TONES decoder
will decode the tones sequence obtained from the modulation meter.
The decoded sequence will appear in the panel at the top of the display, with the first 10 characters
underlined. The sequence decoder store can hold up to 40 decoded characters. Any received in
excess of this will be lost.