"The TX-500 transceiver only supports the Kenwood TS-2000 protocol command set: ID; AI; RX; TX; IF; FA; FB; MD (6-DIG); FR; FT; FN; PA; RA
The protocol does not support commands such as AF Gain, RF Power, Keyer settings.
The TX-500 transceiver was developed primarily as an ultraportable field transceiver for outdoor use in difficult conditions, and it was supposed to be used as an independent self-sufficient unit."