In plain language: CAT control is a command interface that lets software read or change supported radio functions such as frequency, mode, VFO, filters, and sometimes PTT.
Why the station behaves this way
The command set, baud rate, USB driver, CI-V address, cable wiring, and control capability are radio-specific. CAT and audio are separate functions even when one USB cable carries both.
A common wrong turn
A program that displays the frequency correctly may still key the wrong VFO or fail to put the radio in the required data mode.
What to do at the radio
Use the radio’s documented protocol and driver, match port settings, test read and write commands without transmitting, confirm VFO and mode behavior, then add PTT only if needed.
Operating boundary
Use current equipment instructions, legal operating limits, the exact signal path, and observed conditions. A connector, software label, transformer ratio, or forecast value does not prove complete-system performance.
