mgrant@cos.com (Michael Grant) (11/29/88)
Well, I just had C&P telephone solve my repetitive problem for me. Once I got in touch with the right person, (a trunk trouble shooter), it was easy. He tells me that the problem presents itself when you have a T1 trunk that goes from a #5 ESS all digital central office into an analog central office. The problem presents itself when they forget to install, or improperly configure a board in the T1 carrier system equipment (this is not the analog switch, but before the switch) called an "OIU board". He didn't know what OIU stood for, but he tells me that it's fairly standard telco terminology. He said that this board provides the clocking for the link going from the analog office to the digital office. Without the board, the T1 carrier system uses a different clocking source (presumably an internal clock within the T1 equipment) which is not always quite in sync with the correct source. That's why things appear to work ok for voice, but not for data.