British Telecommunications Plc’s ISDN 2 Multiplexer upgrade programme is causing some ISDN devices to fall over, leaving users unable to make outgoing calls. The programme, which began in May and will finish towards the end of the year, is being undertaken on a roughly north-south basis, which means that the next few months will see many users in London and the Home Counties unable to use their adaptors without modification. BT is upgrading the multiplexers to ensure its basic rate ISDN service conforms to the European Community Memorandum of Understanding on ISDN expansion in Europe, but has found that while many adaptors work with both the old and new IMUXs, some require software changes to operate with the replacements. The two vendors known to be affected: Bracknell, Berkshire-based Gandalf Digital Communications Ltd, and Bournemouth-based 4-Sight International Ltd – are having to wait for users to report difficulties before they supply the replacement PROM. 4-Sight in particular has suffered from the phased roll-out since the upgraded PROM for its NuBus ISDN Macintosh board will not work with the old IMUXs. For this reason, the company has had to wait for a problem to be reported before it can act. In its defence, BT says that major manufacturers’ ISDN products were tested at its Martlesham Laboratories and affected suppliers were informed prior to the change. However, Gandalf says that it was unable to take preventative action. Many sales of its affected TA1 basic rate interface board are via dealers and distributors, so it has no comprehensive record of its customer base. It has organised a package that enables users that experience problems either to send back their adaptor and have the PROM upgraded free, or pay UKP50 for an on-site visit. Just how many manufacturers’ adaptors have been affected is unclear since vendors are understandably cautious in publicising difficulties, and BT says it would be unfair to make its information public. According to sources within Gandalf, the company has had a fair few adaptors returned, but 4-Sight says that so far it has encountered only one case. The problems will become more frequent over the next few months as the software changes reach the ISDN heartland in the south.
