CMX641A DUAL SPM/SECURITY DETECTOR/GENERATOR D641A/5 January 2002 Provisional Information Features Applications Two (12kHz/16kHz) SPM Detectors SPM for Pair-Gain Systems Selectable 12kHz/16kHz ASK Generator Payphone Security Applications Selectable Tone Follower or Packet Call Charge Applications in PBX and Mode 3-State Outputs PABX Line Cards Excellent Speech-Band Rejection Out-of-Band Signalling Systems Hardwired Control for Non-C Systems Low-Voltage FX/MX641 Replacement Selectable Bandwidth Limits and Stable C Software-Programmable Secure Centre Frequency from a Standard Xtal Payphone Call Charging Apparatus 1.1 Brief Description The CMX641A is a low power, system selectable Dual Subscriber Pulse Metering (SPM) Detector two detectors on a single chip to indicate the presence on a telephone line of either 12kHz or 16kHz telephone call charge frequencies. The detection sensitivity, frequency and bandwidth are independently selectable for each channel, under C control, as is the frequency of the security tone generator, which may be ASK modulated by an external signal. The CMX641A is also backwards compatible with the FX641 and MX641 dual SPM detectors, whilst offering a lower (3.0V) operating voltage and power. The CMX641A has two modes of operation: (1) Fixed Bandwidth Operating state, in which the two channels are set to the same system frequency and sensitivity setting. Sensitivity and system frequency can be under either C or external control. This state is fully pin and function compatible with the FX641 and MX641. (2) Enhanced Features Operating state, under C control, in which each channel has independently controllable sensitivity, bandwidth and system frequency (12kHz or 16kHz). There is also a 12kHz/16kHz transmission tone which can be keyed on and off directly by a dedicated logic pin. This device is suitable for PBX/PABX line-card installations, payphone security applications and pair-gain systems. It is available in 24-pin plastic DIL and SOIC packages and consumes 1.2mA at 3V. 2002 Consumer Microcircuits Limited Dual SPM/Security Detector/Generator CMX641A CONTENTS Section Page 1.1 Brief Description..................................................................................1 1.3 Signal List ............................................................................................4 1.4 External Components..........................................................................8 1.5 General Description.............................................................................9 1.5.1 Description of Blocks .............................................................9 1.5.2 Operating States ...................................................................10 1.6 Application Notes ..............................................................................15 1.6.1 Signal Input Configurations .................................................15 1.6.2 Crystal/Clock Distribution ....................................................15 1.6.3 Channel 1 and Channel 2 Output Format ............................15 1.6.4 Setting Level Sensitivity via Input Serial Data Word...........16 1.6.5 Setting Level Sensitivity via External Components............17 1.6.6 Aliasing..................................................................................17 1.6.5 Settng Level Sensitivity via External Components.............18 1.7 Performance Specification................................................................19 1.7.1 Electrical Performance..........................................................19 1.7.2 Packaging..............................................................................24 2002 Consumer Microcircuits Limited 2 D/641A/5