Abstract: A method and apparatus for a computer-telephone interface system by which a general purpose personal computer is enabled to perform telephone functions such as dialing, answering ringing lines, and placing lines on hold without the need for a separate telephone instrument. The interface system is responsive to digital signals received from a microprocessor in the computer to implement the signalling functions utilized in a standard switched telephone network. The interface system performs dialing sequences entered either from the keyboard of the computer, a location in the computer memory, a location on a display screen associated with the computer or a location specified by a cursor used in association with the keyboard. Operation of the interface system does not interfere with the concurrent operation by the computer of an applications program.