Service Manual Part 1
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In MTM, the following operations are common to T203X, T2040 and T2060 radios:
• A short beep is sounded after every key press.
• All models accept the reset command character (^).
• The microphone PTT switch functions as in normal operation, i.e. a PTT press/
release selects transmit and receive respectively.
• LEDs or LCD annunciators are used to indicate transmit, synthesiser lock status and
receive signal detect status (refer to Table 5.2, “Radio Mode/Status Display”).
MTM can also be selected by sending the MTM select command while in
CCTM or program mode (refer to Table 5.1, “T2000 Test Facilities”), then
switching the radio off then on again.
This mode selection is ‘sticky’, in that the radio will always power- up in MTM
if no serial device logs on, regardless of the state of the test link. This automatic
mode selection can only be cleared by sending the appropriate command (refer
to Table 5.1, “T2000 Test Facilities”).
Increment channels in MTM by shorting S14 pin 10 (/EMRGNCY) to ground.
When the highest channel is reached, the next increment selects the lowest
channel.
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Four preset channels are available via the four preset keys to , and their
associated LEDs show the current channel. All four channels can be programmed to any
frequency within the full coverage band of the radio.
• selects the channel with the lowest number (i.e. the lowest channel in the net-
work).
• selects halfway between the highest and lowest channels available, rounding
up to the nearest channel.
• selects the channel with the highest number (i.e. the highest channel in the
network).
• selects the first channel in the normal hunt list.
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• To select a channel, enter the channel number required using the front panel keys,
and press the
key .
• The
key enables & disables the minimum shift keying (MSK) modem
transmit, and the
LED momentarily shows status. Action of the key is push-on/
push-off. When the modem transmit is enabled, the microphone audio is muted and
when the modem transmit is disabled, the microphone audio is unmuted.
When the radio is in receive, the modem transmit is temporarily disabled (and the
microphone audio is muted), but this is not shown by the
LED.
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