We use your FREQ Counter output RCA jack. Every time you key it provides a connection between the +/- of the RCA connector.
1) Output RCA completely isolated from the radio. The RCA connects to a relay that isolates it from the radios circuits.
2) Optional BYPASS switch in case your external device does not have one. (turns port off (stays open))
3) Works all the time in high or low power modes..
4) Heavy duty relay can handle any keying circuit voltage, even the SB-220’s – 120VDC circuit.