On Tue, July 22, 2025 5:45 pm, Nick England wrote: > On my 136A — running full duplex. > On PRINT ENABLE > Off ECHO > On PRINT > AUTO PRINT > I tied DSR to DTR (pins 3-4) If this is standard EIA232, I think 3 and 4 are RTS and CTS. 8 and 20 (as I recall from 40 years ago) are DSR and DTR... Harold https://w6iwi.org -- Not sent from an iPhone.