Pair Gain Dual SPM Detector

The CMX661 is a low power, 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 frequency and bandwidth are common to both detectors and may be externally selected. The detection sensitivity is set independently for each channel by external components and the detector outputs can be set to a high impedance state for device multiplexing requirements in PBX and PABX line card applications.

FEATUREs
• Two (12kHz/16kHz) SPM Detectors
• Standard 3.579545MHz Xtal
• Selectable Bandwidth Limits
• Excellent Speech-Band Rejection
• Low Power 3.0V to 5.0V Operation

APPLICATIONs
• Pair-Gain Systems
• Out-of-Band Signaling Systems
• Call Charge Applications in PBX and PABX Line Cards