I've tried this using my A500+ and A1200
I'm using a USB to Serial adapter on my PC + Null modem cable connected to the Amiga.
On the PC side I use Internet Modem by Boycott software to emulate a Hayes modem.
On the Amiga side I've tried Ncomm and JRComm
All the Amiga settings are fine as I even had someone give me an ADF of their Ncomm disk which works perfectly for them.
I just matched the settings with my PC i.e 19200, 8N1 etc.. etc..
Problem is on the Amiga I cannot get ANSI to work. ASCII (black n white is fine)
Tried multiple BBS's which work fine when I connect to them using a PC but on the Amiga no ANSI color.
Also on the Amiga upper and lower case are switched but not on the PC.