6. WITHDRAWAL OF BOTHWAY ANALOGUE DDI
As explained in Newsletter No. 117 back in December 1999, Telecom's recent generations of access transmission systems do not support bothway analogue Direct Dialling-In (DDI).
The Telecom PSTN, like most overseas networks, has traditionally always aimed for backwards compatibility with existing customer equipment. As a result, some of our services are based on very old technologies and practices. For example, our reverse decadic dialling originally dated back to the 1920’s. Although it is rarely used these days, the Telecom PSTN still supports this mode of signalling.
Another such “legacy” service is analogue Direct Dialling-In (DDI), which allows a caller direct access to individual extensions of an analogue PABX. Bothway analogue DDI was to have been withdrawn for new customers some years back, when we first started purchasing access multiplex systems which do not support Bothway analogue DDI as part of their basic design. Unfortunately, it now appears that the service has continued to be provided for those parts of the network where there are lines that still support it. As a result, more customers have been provided with this service than we originally
anticipated and they will be impacted when the Next Generation Network replaces the present NEAX network will be higher than we had expected.
Telecom is faced with two options: either call on manufacturers of new access and switching equipment to make special provision for traditional services like our analogue DDI; or face the fact that this technology is outmoded and start to withdraw this service.
This matter is again under consideration within Telecom and it is fairly certain that Bothway analogue DDI will no longer be offered to new customers some time in 2006. This decision will impact on PABX suppliers and the types of trunk interface cards they will be importing, so the above should be regarded as “a second early warning” of this change.
More on this subject will be published in future Newsletters.
Doug Burrus
Manager
Access Standards
