M-959

The M-959 is a low-power dial pulse counter and hook status monitor. Contained in a 14-pin package, the M-959 requires no external components except a single 3.579 MHz television color burst crystal.

The M-959 is typically connected to a loop current sensing circuit, which is connected in series with the voice pair (Tip and Ring) of a telephone line. The M- 959 receives pulses from the loop current sense circuit and translates them into logic level outputs indicating hook status and decoded dialed digits. Logic inputs to the M-959 select dialed digit speeds and control Data and Strobe outputs supporting bus interrupt driven implementations.