Circuit Packs That Use The Packet Bus - Avaya MCC1 Maintenance Procedures

Packet and serial bus maintenance
Isolating and repairing packet-bus faults
• TN556 ISDN-BRI:
— BRI-BD/LGATE-BD (ISDN-BRI Line Circuit Pack)
— BRI-PORT (ISDN-BRI Port) ABRI-PORT (ASAI ISDN-BRI Port)
— BRI-SET, BRI-DAT, Various Adjuncts
• TN464F Universal DS1:
— UDS1-BD (UDS1 Interface Circuit Pack)
— ISDN-PLK (ISDN-PRI Signaling Link Port)
• TN771D Maintenance/Test:
— M/T-BD (Maintenance/Test Circuit Pack)
— M/T-DIG (Maintenance/Test Digital Port)
— M/T-PKT (Maintenance/Test Packet Bus Port)

Circuit packs that use the packet bus

This section describes the circuit packs that use the packet bus and the mutual effects of circuit-pack and
bus failures.
Seven circuit packs use the packet bus: The MOs associated with each circuit pack are listed in brackets:
• TN2312AP IP Server Interface [PKT-INT] provides a server's Ethernet interface to a PN's
packet bus. All traffic on the packet bus passes through the TN2312AP IPSI circuit pack's Packet
Interface circuit. This circuit can detect some control-lead and many data-lead failures by
checking for parity errors on received data.
• TN570 Expansion Interface [EXP-INTF] connects the PNs in the system. All packet traffic
between PNs passes through a pair of TN570s (one in each PN). The EI can detect some control-
lead and many data-lead failures by way of parity errors on received data.
• TN556, TN2198, or TN2208 ISDN-BRI [BRI-BD, BRI-PORT, ABRI-PORT, BRI-SET, BRI-
DAT, ASAI-ADJ] carries signaling information for ISDN-BRI station sets and data modules, as
well as signaling information and ASAI messages between the server and an ASAI adjunct.
Depending upon the configuration, an ISDN-BRI circuit pack has the same fault-detection
capabilities as a TN570 EI circuit pack can detect some control-lead and many data-lead failures
by way of parity errors on received data.
• TN464F Universal DS1 circuit pack [UDS1-BD, ISDN-LNK] supports ISDN-PRI
communications over an attached DS1 facility. It transports D-channel signaling information over
the packet bus, and B-channel data over the TDM bus. Depending upon the configuration, the
universal DS1 circuit pack has the same fault-detection capabilities as a TN570 EI circuit pack
can detect some control-lead and many data-lead failures by way of parity errors on received data.
• TN771D Maintenance/Test circuit pack [M/T-BD, M/T-DIG, M/T-PKT, M/T-ANL] is the
workhorse and a critical tool of packet-bus maintenance. This circuit pack can detect every
packet-bus fault in the PN where it resides. In a critical-reliability system (duplicated PNC), this
circuit pack enables the reconfiguring of the packet bus around a small number of failed leads.
The TN771D circuit pack provides a stand-alone mode (one not involving indirect
communication with the server, through the IPSI) for inspecting packet-bus faults.
222 Maintenance Procedures
December 2003