Service Manual Part 1
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• The
key selects MSK modem transmit test patterns. The
LED
is off for zeros, on for ones and flashing when preamble is being sent. Successive
depressions of the key will scroll through the three states. Whenever the
key is pressed, the modem transmit is enabled unless the radio is in receive, in
which case the
LED will illuminate momentarily.
• The
key controls the transmit power output of the radio. The
LED
is off for low power, on for high power and flashes when maximum power has been
selected. Successive depressions of the key will scroll through the three states.
Each time the channel is changed, the transmit power is reset to the level pro-
grammed for the new channel and is indicated by the
LED.
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Test functions are selected by entering a two digit number followed by the
key .
Channels are selected by pressing the key (“Chan” will appear in the display),
followed by a one to four digit channel number and terminated with the
!
key.
After every valid command execution, a confirmation will appear in the control head
display in the form of a message. A confirmation tone is also sounded. Entries that are
invalid for any reason, e.g. an invalid function or channel number, result in a displayed
message and a warning tone.
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In CCTM, test commands are accepted via the serial port of the radio and test results are
returned as required. To send and receive commands from the radio it is necessary to
run a ‘dumb terminal’ emulation program on a PC.
The serial communications port parameters are as follows:
• Logic levels:
Out: 0V = ‘1’, +5V = ‘0’
In: -12V to 0V = ‘1’, +3V to +12V = ‘0’
• A programming lead may be used to convert the output to RS232 voltage levels.
• No handshaking (RTS, CTS etc. not implemented).
•Full duplex.
• 4,800 baud.
• One start bit, eight data bits, one stop bit, no parity.
• Flow control: X
on
/X
off