DEFINITY Enterprise Communications Server Release 7
Maintenance for R7r
555-230-126 Issue 4
June 1999
Alarms, Errors, and Troubleshooting
5-66Troubleshooting ISDN-PRI Problems
5
When a downgrade does oc cur, information on the Status Conference form
indicates the succ ess or failure of the 64kbps-endp oints that are participants to
properly rate adap t to 56kbps. As a general ind ication that the conference has
rate adapted, the Conference Transfer Rate and Effective Transfer
Rate fields show initial and current transfer rates, resp ectively. For each 64-kbps
endpoint the column that in dicates Rate Adapt shows an n if the endpoint did
not follow the procedures as spec ified by the H.221. If an endp oint shows y, it di d
successfully rate adap t. If an endpoint shows c, it joined the conference at
56kbps.
Once the conference rate ad apts, the endpoints that d o not properly follow suit,
will become audio-only end points. A conference will not rate adapt from 56 kbps
back to 64 kbp s until all endpoints disc onnect from the conference and it idles.
The PictureTel 1000 Release 1.1C, PictureTel 6.01 software, and the Vistium 2.0
software successfully rate ada pt with the MCU. External rate adaptation
techniques used b y VTEL and CLI are known to cause problems with the
endpoint when used with this fe ature.

Endpoint or I-MUX in Loopback Mode

Some endpoints have a loopbac k enable feature. This makes DEFINITY MMCH
data loopback at the MMCH when a connection is in progress. The loopback can
be enabled p rior to or during a connec tion.
The MMCH does not detect the loop and continues to VAS. In most scenarios,
the switch occurs, b ut within a few seconds, the broad caster’s return video
becomes its own image. Onc e the broadcaster stop s speaking, the system
“false” switches to an ap parently random port that was not speaking.
Troubleshooting ISDN-PRI Problems
The following flow chart defines a l ayered approach when troub leshooting
ISDN-PRI problems. Since a problem at a lower layer affec ts upper layers, layers
are investigated from low to high. In t he flowchart, the DS1 facility is layer 1, the
ISDN-PRI D-channel is layer 2, and the ISDN trunks are layer 3. Transient
problems are diagnosed on Page 2 of the flowchart. For problems wi th PRI
endpoints (wideb and), see the following section.