KPC-9612 Version 5.2 July 19, 1994
59
Pin 9 This pin connects to the ground of your 9600 baud radio.
Pin 10 This pin is connected to ground (same as pin 9).
Pin 11 This pin is connected to ground (same as pin 9).
Pin 12 This pin is the receive clock signal. You may use this pin to connect to an oscilloscope trig-
ger input to observe the eye-pattern of a 9600 baud signal. The RXA signal (pin 2) would
connect to the vertical input to the scope.
Pin 13 When a ground is applied to this pin and the KPC-9612 CD command is set to EXTERNAL,
the KPC-9612 will not transmit packet. This is normally used as an external means of sup-
plying carrier detect to the KPC-9612.
Pin 14 Not connected.
Pin 15 Not connected.
Transmit level adjustment
1200 Baud
The AFSK drive level from the KPC-9612 may be adjusted using potentiometer R-22 and jumper
J5. When the J5 jumper is placed on one post only, the output level may be adjusted from
2 mVp-p to 60 mVp-p. Placing the jumper on both posts allows adjustment from 140 mVp-p to
4 Vp-p. This level should be adjusted to provide approximately 3.5 kHz deviation on your radio.
9600 Baud
The 9600 baud drive level from the KPC-9612 may be adjusted using potentiometer R-32 and
jumper J7. When the J7 jumper is placed on both posts, the output level may be adjusted from
80 mVp-p to 4 Vp-p. Placing the jumper on one post only allows adjustment from 2 millivolts p-p
to 100 millivolts p-p. This level should be adjusted to provide approximately 3.0 kHz deviation on
your radio. If your radio will transmit properly with J6 on both posts (dc coupled), we recommend
this setting.
Watchdog Timer
The KPC-9612 has a push-to-talk watchdog timer for both ports. These timers are both enabled at
the factory with jumpers J4 (1200 baud) and J3 (9600 baud) on just one post. If the KPC-9612 at-
tempts to keep your radio transmitting continuously for over 2-½ minutes on the 1200 baud port
or more than 30 seconds on the 9600 baud port, the watchdog timer will activate and release the
PTT line to your radio. Current FCC regulations require a watchdog timer to detect such a failure
and stop the transmission.
Microprocessor Watchdog Timer
The KPC-9612 includes a watchdog tinier for the microprocessor. In the unlikely event that your
TNG firmware gets in a loop, the watchdog timer will detect the failure and force a soft reset of
the KPC-9612. No parameters will be lost due to this reset.
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