Wikipedia
GT Power is a bulletin board system (BBS) and dial-up telecommunications/terminal application for the DOS family of operating systems. It was first introduced in the 1980s by P & M Software, founded by Paul Meiners. GT Power can be used both to host a BBS as well as to connect to other BBS systems via its full-featured dial-up "terminal mode." GT Power was a shareware package that required a registration fee in order to access its proprietary network mail transport/handling software and, by default, the GT Power Network. The software is distributed in two "flavors"; a terminal-only version, nicknamed GTO, and the full-featured host and terminal version.
The source code for GT Power was sold twice during the late 1990s, again in 2008 and is currently the property of Tom Watt.
Although GT Power was written to run under DOS, it is also quite capable under the Microsoft Windows (versions with DOS support) and OS/2 / eComStation operating systems. When it is running under OS/2 or eComStation, GT Power can also be used as a telnet BBS host and terminal program via use of an OS/2 shareware virtual modem application called VMODEM.