Avaya 03-300430 User Manual

The packet bus consists of a single bus, and one such bus appears in each port network. The 
packet bus in each port network is physically independent from those in other port networks, so 
each port network has a separate PKT-BUS MO. This bus supports the following types of 
connections:

●

Logical control links between the media server and every PN

●

ISDN-BRI D-channel transport (signaling)

●

ASAI D-channel transport (signaling)

●

ISDN-PRI D-channel (signaling)

●

X.25 system adjunct signaling and traffic

●

System Access Ports

The TN2312AP IPSI circuit pack’s Packet Interface circuit provides the media server an 
interface to the packet bus. Packet-bus testing depends on the TN771D Maintenance/Test 
circuit pack, the TN2312AP IPSI circuit pack’s Packet Interface circuit, TN570 Expansion 
Interface circuit pack, and various port circuit packs (including TN556 ISDN-BRI Line, TN553 
Packet Data Line, and TN464 Universal DS1). Packet Bus tests may abort if some of these are 
absent from the system. The tests may yield inconsistent results if any of this hardware is 
defective. The individual test descriptions provide more information.
The interactions between the packet bus and the circuit packs that use the bus are complex. 
Circuit pack failures can alarm the packet bus, while packet-bus faults can alarm or interrupt 
service to one or more circuit packs and their ports and endpoints. The 

 section in Maintenance Procedures (03-300192) describes packet-bus 

maintenance and interactions with circuit packs. That section should be referenced for all 
troubleshooting and repairs. The flowchart is the normal starting point for experienced 
technicians.

1.  P is the port-network number indicated in the PORT field from the Alarm or Error Log.

PKT-BUS

MAJ

test pkt P l r 2

1

Packet Bus

PKT-BUS

MIN

test pkt P l

Packet Bus

PKT-BUS

WRN

test pkt P l

Packet Bus