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DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si
555-230-127
Issue 1
August 1997
Packet Bus Fault Isolation and Correction
Page 9-3Tools for Packet Bus Fault Isolation and Correction
9
The Maintenance/Test Packet Bus port (described in detail later in this chapter)
can give the remote technician information about the state of the packet bus.
This information can be obtained via the status system command and via the
PKT-BUS test sequence. As described later, the Maintenance/Test circuit pack
may or may not be present at a customer site, depending on system
configuration. If a Maintenance/Test circuit pack is not present, one must be
taken to the customer site.
In a high or critical reliability system, a Processor Interchange may resolve the
packet bus problem. This operation can be done remotely, and is discussed in
the ‘‘
Packet Bus Fault Correction’’ section in this chapter.
Tools for Packet Bus Fault Isolation
and Correction
The following list discusses several tools that are (or may be) required to perform
Packet Bus Fault Isolation and Correction. The technician should be provided
with these tools at the customer site:
■ TN771 Maintenance/Test circuit pack for use in standalone mode, as well
as the required connectors and cables. (Refer to the ‘‘
The
Maintenance/Test Circuit Pack (TN771D)’’ section in this chapter.)
■ Replacement TN771 Maintenance/Test circuit pack may be needed.
Conditions for requirement, and the relevant implementation steps are
documented in the ‘‘
Special Precaution Concerning the TN771’’ section in
this chapter.
■ Backplane pin-replacement kit may be required in the procedures
described in the ‘‘
Packet Bus Fault Correction’’ section of this chapter. If
the kit is not available, replacement of a carrier may be required.
Packet Bus
Each port network has its own packet bus, and, accordingly, there is one packet
bus MO in each port network. The packet bus is not duplicated, as is the TDM
Bus. However, there are several spare leads on the packet bus and, in high and
critical reliability systems, these spare leads are used to recover from some
failures on the packet bus.
Packet Bus Usage
The packet bus carries ISDN-BRI signaling information for ISDN-BRI stations and
data modules and for ASAI adjunct connections. The TN556 ISDN-BRI circuit
pack is used for these connections. The SPE interface to the packet bus is the
TN778 Packet Control (in high and critical reliability systems, there is one TN778
in each SPE). For systems with multiple port networks, the TN570 Expansion
Interface is used to pass messages from the packet bus in one port network to