A terminal emulator, terminal application, term, or tty for short, is a program that emulates a “dumb” video terminal within some other display architecture. Though typically synonymous with a command line shell or text terminal, the term terminal covers all remote terminals, including graphical interfaces. A terminal emulator inside a graphical user interface is often called a terminal window.
For working with your SMS gate-way Terminal: GSM Modem or Mobile phone, specially for testing the connection, I recommend you to use: “Tera Term”. You will need this software particularly when you work using Windows Vista which doesn’t have HyperTerminal.
Tera Term (Pro) is a free software terminal emulator (communication program) for MS-Windows. It supports VT100 emulation, telnet connection, serial port connection, and so on. Source code (C, C++) available (315 K).
It can be download here