User's Manual

As you can see from the example, the frequency entered was
158.9685 MHz. This is invalid per the rules. The software
responds with a comma, then 6 zeros, and a carriage return. At this
point, the program has not updated your transmitter, and is
awaiting an input instruction (f, v, c, or s) from you. Enter an f
so that you may re-enter a correct, valid frequency.
Programming from a Citation 20 Receiver/Recorder Kit
Please consult your Citation 20 Operations Manual for directions
on programming transmitters directly from the Citation 20,
WITHOUT a separate computer!