DigitMaster Pro Series Tone Decoder hand-held 16 Digit Touch-Tone Decoder (DTMF) with built-in microphone. Decodes touch-tones from any on-air source, scanner or cassette tape. With the DGPRO Portable DTMF Decoder, just play the tape, and the numbers will appear on the LCD display. No connections are necessary! Should you need to decode via patch cord, an input is provided. Powered by a 9-volt battery. (not included).