@sabi 56k but on the line I was able to acquire a usage permit for, I was only ever able to get slightly over 19k2bps, and since I used it with a slower 386 laptop for the first time I used setserial
to configure the COM port down to that so the CPU could keep up with the interrupts
@mirabilos both of these are familiar! Family computer couldn't keep up with a 14.4 modem in Windows but was fine in DOS. Also my dad moved to a very rural town and couldn't get over 21.9