Abstract: A computer interface device for answering calls on a telephone line and transmitting a ring signal and caller identification information to the computer. The interface device is powered by the computer's serial port. The interface device operates in one of two modes of operation. In the call receive mode, the device answers calls and transmits caller identification and ring information to the computer. In the dial mode, the computer places calls on the telephone line. The computer controls activation of the interface device's operational modes.