The Avaya TN775D circuit pack is used in maintenance to monitor power failure signals in an EPN cabinet in R7si/r or later. The TN775D also monitors the clock, monitors and controls the power supplies and battery charger, and monitors air flow and high-temperature sensors.
The TN775D circuit pack provides two serial links to communicate with Expansion Interface (EI) circuit packs, and provides an RS-232 interface for connection to an administrative terminal.
Each circuit pack contains a three-position switch to control emergency power transfer.
The TN775D contains a DC to DC power converter and is used in maintenance to monitor the R7 or later processor in a Survivable Remote Expansion Port Network configuration.