What have you tried, exactly?
PCMCIA Serial and Modem Issues
Multitech MT5634ZLX modem problems (Ray Muno)
Date: 1999, Nov 05
From: David Hinds <email@example.com>
Have you worked through the troubleshooting information for serial
cards in the PCMCIA-HOWTO? My first guess would be something along
the lines of an IO port conflict.
to: "What have you tried, exactly?"