TN420C - TN744E

Avaya Definity TN556B ISDN BRI 4-Wire Interface Circuit Pack

  • Like New: $59.00
Availability: In Stock

TN556B ISDN BRI 4-WIre Interface

Provides 12-ports connecting to ISDN-BRI terminals. Each port uses TXT, TXR, PXT, PXR signal leads and ranges up to 3300 feet maximum from the system to the voice terminal.


  • Ports connection to ISDN-BRI terminals: 12
  • Signal leads: TXT, TXR, PXT, and PXR
  • Up to 8 ports can be used for ASAI links
  • 2 B-channels
  • 1 D-channel
  • Range up to 3300 ft.
  • Compatible with Definity R7 or late
  • Requires a packet control circuit pack (TN778) if using R6si systems
  • Includes Atlas 1-Year Warranty with Extended Warranty options available!

Package Includes

  • TN556B ISDN BRI 4-WIre Interface

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