Hello,
It sounds more like a handshaking issue, you might be using a really 'dumb' Null Modem cable with just TXD, RXD and GND lines wired through - What you want is a setting like 2400,N,8,1
Ie: 2400 baud, No parity, 8 data bits, no stop bits (turn off any flow control under NComm and on your PC such as RTS/CTS and DTR/DSR)