Abstract: A modem sharer for interconnecting a plurality of remote terminals with a modem for the transmission of data between the terminals and the modem. The modem sharer includes a request to send circuit having a timer, a data transmission gating circuit, and a clear to send circuit. The raising of a request to send signal at a selected terminal actuates the timer and initiates signal transmission if cleared for transmission. Transmission is interrupted if not completed within a preset time set into the timer. Then, remaining terminals are free to transmit. LED displays indicate modem sharer operation, including an offending terminal which is not transmitting properly. The modem sharer is short circuit protected, and is capable of operating in a piggyback array.