Abstract: A data/voice adapter apparatus for use in a telephone network having two or more stations interconnected by telephone lines. Each station typically includes a computer and associated modem together with a telephone handset. The modem and handset are coupled to the telephone through the subject adapter. When the adapter is in a dial mode, dialing signals are transferred from either the modem or telephone handset to the telephone line so that a telephone hookup to another station can be created. Once the hookup is made, the adapter can be switched to a split mode whereby a relatively low frequency channel is provided for voice communication utilizing the telephone handsets and a relatively high frequency channel is provided for simultaneous data communication utilizing the modems.