SMS is a small and user friendly program for sending text messages to GSM cellular phones from a Macintosh. The text message is typed in a normal text window, and must be less than 160 characters. The program dials a GSM carrier, which will transmit the message to the GSM mobile. SMS waits for an acknowledge from the GSM cellular. If the GSM cellular was not accessible, the message will be saved by the GSM carrier, and later retransmitted.