Full list of features

General
Virtual modems look and work like real hardware modems
Applications use virtual modems directly from virtual serial ports or through TAPI
Virtual Modem can originate or answer TCP connections with any other device, including computers running another copy of the Virtual Modem.
Up to 256 virtual modems can be created
Virtual modems are compatible with fax software
Virtual modems work with IP Fax Machines
Virtual modems can "dial" to remote virtual modems using IP address (or computer name) and TCP-port instead of phone number
Virtual modems can accept "incoming calls" from other virtual modems
Phone book. It allows you to simplify switch to virtual modems from hardware modems. You can specify telephone number corresponding to IP address (or computer name) and TCP-port of remote virtual modems.
Once created virtual modems are operable at each system startup (even prior to user login)
Compatibility
Support of main AT commands
Support of main S-registers
User interface
User-friendly program interface
Hot virtual modem creation and removal, without computer reboot