Files with em$ extension are used by the Cheyenne Bitware fax and calling software.
EM$ file extension - Cheyenne Bitware file
What is em$ file? How to open em$ files?
File type specification:
The em$ file extension is associated with the Cheyenne Bitware fax and calling software for computer modems developed by Cheyenne Software, Inc. The .em$ file stores various data used for internal purposes of the Cheyenne Bitware.
Cheyenne Bitware seems to be obsolete product.