In some bureau, there are about 25 terminals, with most of them are out of the local province, being connected with the ISDN network. The MCU and each terminal can be connected in normal debugging. But when there is a associated research conference, the dialing rate of other council houses is so low and can’t join the conference after the first ten council houses join the conference.
Each terminal dial the MCU and get such information “no circuit or path available”, “no information unit content/format available”
Sent this problem to the telecom, then the telecom expands the path source after analyzing the problem. When the next associated research conference is held, the problem is solved.
With the ISDN network, suppose each terminal corresponds with 6 B channels. When there is a conference, if there are 25 council houses, we need 180 B channels, however, the number of digital path between telecom long-distance bureau and MCU is limited, and it can’t meet the demand of path source in a associated research conference. After the bureau expands the path source, the problem is solved.