Lucent Technologies Release 7 Tools for Packet Bus Fault Isolation and Correction, What is the Packet Bus?

DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4 June 1999
Alarms, Errors, and Troubleshooting
5-80Packet Bus Fault Isolation and Repair
5
Tools for Packet Bus Fault Isolation and
Correction
The following tools may be required o n-site to perform pac ket bus fault isolation
and correction.
■TN771D Maintenance/Test circuit pack for use in stand alone mode, and
the connectors and c ables necessary to install it (see the
Maintenance/Test Circuit Pack section).
■A replacement for the TN771D Maintenance/Test circuit p ack in the
system may be needed. See the
A Special Precaution Concerning the
TN771D
section.
■A backplane pin-replacement kit may be required (see Packet Bus Fault
Correction
) If the kit is not available, replac ement of a carrier may be
required.
What is the Packet Bus?
The packet bus is a set of 24 lead s in the backplane o f each Port Network.
Twenty of these leads are data leads, three are control lead s, and one lead is a
spare. This distinction is imp ortant only for understanding why some circuit
packs are able to d etect only certain faults; the d istinction does not affec t fault
isolation and repair. Each Port Network has its own p acket bus and there is one
packet bus maintenanc e object (PKT-BUS) in each port network. The packet b us
is not duplicated as is the TDM Bus. There are however several spare leads on
the packet bus and , in Critical Reliability systems (dup licated PNC), these spare
leads are used to recover from some fai lures on the packet bus.
The packet bus carries various types of information:
■Signaling and data traffic destined for other port-networks and/or Center
Stage Switches. The TN570 Expansion Interface circuit p ack provides
packet bus ac cess for these connec tions.
■ISDN-BRI signaling information for ISDN-BRI stations, data modules and
ASAI adjunct connections. The TN556 ISDN-BRI circuit p ack provides
packet bus ac cess for these connec tions.
■X.25 signaling information and data traffic to supp ort system adjunct
applications. The TN577 Packet Gateway circuit pack provides packet
bus access for these connections.
■ISDN-PRI signaling information carried in the D-c hannels of ISDN-PRI
facilities connected to the switch. The TN464F Universal DS1 circuit pack
provides pack et bus access for these c onnections.
■System Port tra ffic to support various input/output devices such as dial- up
modems and printers, as well as system adjunct app lications. The TN553
Packet Data circuit pac k provides pac ket bus access for these
connections.