CMX641A
DUAL SPM/SECURITY
DETECTOR/GENERATOR
D641A/5 January 2002
Provisional Information
Features
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Two (12kHz/16kHz) SPM Detectors
Selectable 12kHz/16kHz ASK Generator
Selectable Tone Follower or Packet
Mode 3-State Outputs
Excellent Speech-Band Rejection
Hardwired Control for Non-µC Systems
Selectable Bandwidth Limits and Stable
Centre Frequency from a Standard Xtal
Applications
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SPM for Pair-Gain Systems
Payphone Security Applications
Call Charge Applications in PBX and
PABX Line Cards
Out-of-Band Signalling Systems
Low-Voltage FX/MX641 Replacement
µC Software-Programmable Secure
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 µC 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 µC or
external control. This state is fully pin and function compatible with the FX641 and MX641.
(2) Enhanced Features Operating state, under µC 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
CMLMICRO [ CML MICROCIRCUITS ]
