MX631

The MX631 is a low-power, system-selectable Subscriber Pulse Metering (SPM) detector that indicates the presence of both 12kHz or 16kHz telephone call- charge frequencies on a telephone line.

Deriving its input directly from the telephone line, input amplitude/sensitivities are component adjustable to the user's national !(R)Must/Must-Not Decode specifications via an on-chip input amplifier, while the 12kHz and 16kHz frequency limits are accurately defined by the use of an external 3.579545MHz telephone-system Xtal or clock-pulse input.

The MX631, which demonstrates high 12kHz and 16kHz performance in the presence of both voice and noise, can operate from either a single or differential analog signal input from which it will produce two  individual logic outputs:
  1.Tone Follower Output - A 'tone-following' logic output producing a !°Low!± level for the period of correct decode and a !°High!± level for a bad deco or N OTONE.
  2.Packet (Cumulative Tone) Mode Output - To respond and/or de-respond after a cumulative 40ms of good tone (or NOTONE) in any 48ms period. This process will ignore small fluctuations or fades of a valid frequency input and is available for ?Processor !(R)Wake-Up!, Minimum Tone detectio NOTONE indication or transient avoidance.

This system (12kHz/16kHz) selectable integrated circuit, which may be line-powered, is available in 16-pin plastic DIP and SOIC surface mount packages.