Summary
Phone Line Monitor with Detectors (PLMD)
Description
The CPC5712 is a special purpose Phone Line Monitor with Detectors (PLMD) integrated circuit that is used in various high-voltage telephony applications such as VoIP gateways and IP-PBXs. The device monitors the TIP/RING potential through a high-impedance divider (resistor isolation) to derive two programmable signal level detects, polarity information, and a scaled representation of the phone line voltages. In use, the resistor divider and the high input impedance of the CPC5712 make the circuit practically undetectable on the line.
Source title
CPC5712 Datasheet(PDF) - Clare, Inc.