M-959
Dial Pulse Counter and Hook Status Monitor
Features
•
Time-guarded dial pulse counting
•
10 or 20 PPS dialing speeds pin selectable
•
Tri-state data outputs
•
Valid data output strobe
•
Data strobe control for use in interrupt-driven
environments
•
Independent hook status monitoring
•
Low-power CMOS construction
Description
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 cir-
cuit 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.
Pin Diagram
Ordering Information
Part #
M-959
Description
14-pin plastic DIP
Block Diagram
DS-M959-R3
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