I made a Lua script for FSUIPC7 that sets the active frequency to a dummy frequency when COM CIRCUIT ON is off, and restores it to the previous frequency when COM CIRCUIT ON is on, for COM1 and COM2 separately. (Initially I tried using SI's start/stop ATC keybind, muting the whole SI app, changing COM volumes, and changing COM receive selection, but changing the frequency worked out the best.)
Requires the payware version of FSUIPC7 to run.
com1_power_offset = 0x66DE -- A:CIRCUIT COM ON:1
com2_power_offset = 0x66DF -- A:CIRCUIT COM ON:2
com_active_hz = {}
com_active_hz[com1_power_offset] = 0x05C4
com_active_hz[com2_power_offset] = 0x05C8
RADIO_SET_HZ = {}
RADIO_SET_HZ[com1_power_offset] = 67240
RADIO_SET_HZ[com2_power_offset] = 67242
stored_frequency = {}
stored_frequency[com1_power_offset] = nil
stored_frequency[com2_power_offset] = nil
dummy_frequency = 111000000
function check(power_offset,power_status)
if power_status == 0 then
stored_frequency[power_offset] = ipc.readUD(com_active_hz[power_offset])
ipc.control(RADIO_SET_HZ[power_offset],dummy_frequency)
else
if stored_frequency[power_offset] then --script is meant to be run before radios are first turned on, but check just in case
ipc.control(RADIO_SET_HZ[power_offset],stored_frequency[power_offset])
end
end
end
event.offset(com1_power_offset,"UB","check")
event.offset(com2_power_offset,"UB","check")
