The Telex DSP-223 provides a reliable means of remotely controlling two-way radio base stations. The adapter can be used in conjunction with all radio dispatch consoles, or other manufacturers’ (such as Motorola and GE) remote consoles that use the industry-standard sequential tone-keying format. The DSP-223 is interconnected to the distant remote control console(s) by any voice-grade transmission medium, such as a microwave link, leased telephone line, or a twisted pair 600-ohm line. All DSP-223s are capable of decoding the PTT (push-to-talk/transmitter-on) tone sequence and the voice-plus-tone signals during transmission. All models are prepared for jumper plug conversion from two-wire line operation to four-wire line operation. In the four-wire mode, the panels are full-duplex capable.