Check the listing for details. Avaya Lucent Definity Phone System TN775B Maintenance Card Pack. Condition: Used. Listed at 17.95 USD. Avaya Definity Maintenance Card Pack Model Number: TN775B This is a used card, pulled from a decommissioned Avaya PBX cabinet. TN775B Features - Used in maintenance and monitor power failure signals in an EPN cabinet in R7si/r or later. - Monitors clock, power supplies, battery charger, air flow and high temp sensors. - Provides 2 serial links to communicate with Expansion Interface (EI) circuit packs. - Provides an RS-232 interface for connection to an administration terminal. - Contains a 3-position switch to control emergency power transfer. Free domestic shipping via the United States Postal Service. International shipping will be via USPS Priority International, or the GSP. Feedback will be left automatically by the system upon you leaving feedback for us. Please be sure to ask any and all questions BEFORE making your purchase. Any and all returns are subject to a 20% restocking fee.