User manual
DEFINITY Enterprise Communications Server Release 6
Maintenance for R6vs/si 
555-230-127  
Issue 1
August 1997
Maintenance Object Repair Procedures 
Page 10-710ISDN-PLK (ISDN-PRI Signaling Link Port) 
10
on TN464 series circuit packs. A description of these circuit packs appears in 
DS1-BD or UDS1-BD maintenance documentation.
In a 24 channel system, the DS1 ISDN Trunk or PRI endpoint port (B-channels) 
may use any of the first 23 ports. The ISDN-PRI Signaling Link Port must be the 
24th port. In certain configurations (NFAS), the 24th port may be used as a 
B-channel. Refer to the ISDN-PRI Signaling Group (ISDN-SGR) Maintenance 
documentation for further details.
In a 32 channel system, the DS1 ISDN Trunk or PRI endpoint port (B-channels) 
may use any of the ports 1-15 or 17-31, but the ISDN-PRI Signaling Link Port 
must be the 16th port. In certain configurations (NFAS), the 16th port may be 
used as a B-channel. Refer to the ISDN-PRI Signaling Group (ISDN-SGR) 
Maintenance documentation for further details.
ISDN-PLK handles maintenance and recovery for the D-channel port on the DS1 
carrying the signaling link. A problem with the ISDN-PRI Signaling Link Port 
(D-channel) has an effect on all of the associated DS1 ISDN Trunks or PRI 
endpoint ports (B-channels) since no call control information can be conveyed to 
the far-end switch or Terminal Adapter without it. Stable calls may remain 
operational, but no new calls can be made.
The ISDN-PRI Signaling Link Port (ISDN-PLK) itself depends on two other 
entities: the UDS1 interface circuit pack (TN464) it resides on, and the Packet 
bus which provides the link to the processor. If there are problems with the 
ISDN-PLK, also investigate the TN464 UDS1 interface circuit pack (UDS1-BD) 
and the packet bus (PKT-BUS).










