Hmm. Bought a DIN-8 to DB-25 serial converter for this Mac Classic. Seems like it works for receiving data in ZTerm but not sending.

Tried a WIFI232 and a USB serial interface with a Pi, both send text that shows up on the screen. But nothing happens with typing AT commands.

Cable pin connections seem correct after finding a few diagrams online and checking with a meter

Might try looking for another terminal program for System 7, hoping it’s not a hardware problem in the Mac itself.

@kauer WIFI232 pretends to be a modem with AT commands but "dials" over telnet. The RasPi runs tcpser, which does mostly the same thing. I use these with other retro computers with serial ports to "call" telnet BBSes and transfer files

@anna I love these things, except for when they tell me my cables are bad.

Got stuff to do today. But after a morning of the boy cats making her angry, Cheddars is being cozy with me and sighing. I don’t think I get to do things now

Okay so maybe some of the sighing is snoring now. I don’t think she’d tolerate a CPAP mask though

@kauer Yeah, both the Wifi232 and tcpser start up ready for AT commands until dialing out via telnet