This is the v90 Upgrade for the Megahertz XJ1560-CC1560 33.6 PC card modem. The modem is x@ Upgradeable, but Megahertz's USA office will charge fro the firmware ($60!). I found this on a US Robotics affiliate site, freely available for download. Very cool.
The following files are found inside the driver download file.
|disk1.3c||621.0 KB||5 Feb 1998|
|disk2.3c||479.6 KB||5 Feb 1998|
|readme.txt||1.8 KB||5 Feb 1998|
|INSTALL.BAT||899 bytes||5 Feb 1998|