Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!accuvax.nwu.edu!nucsrl!telecom-request From: "John R. Covert 10-Jan-1990 0822" Newsgroups: comp.dcom.telecom Subject: Why 8-digit Numbers Are Impossible in North America Message-ID: <2789@accuvax.nwu.edu> Date: 9 Jan 90 21:36:29 GMT Sender: news@accuvax.nwu.edu Organization: TELECOM Digest Lines: 36 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 10, Issue 21, message 2 of 3 Daniel O'Callaghan at The University of Melbourne writes: >Here is a way to ease area code congestion without being too difficult >to implement in North America. It basically means that the affected >area switches to 8 digit numbers without any other area needing to know. Unfortunately, due to the presence of a large number of No. 5 Crossbar central offices throughout North America, changing the length of telephone numbers is not technically possible without billions of dollars in expenditure in other areas. Unlike countries where most telephone service is provided by either ancient step-by-step or modern electronic offices, the North American Integrated Numbering Plan Area (U.S., Canada, and the 809 Caribbean) is chock full of central offices of an intermediate type. These common control offices store the number dialled, the _entire_ number, in what is known as an Originating Register. This is a hardware register made out of relays, and it has the capability of storing three, seven, or ten digits, plus a flag indicating whether "1" or "0" was dialled first. To implement eight digits _anywhere_ in North America would require costly modifications _throughout_ North America to every originating register in every remaining No. 5 XBar office, many of which are not scheduled for retirement until sometime in the first two decades of the next century. >Cellular sevices could all be moved to say 229, allowing easy identification >of a number as mobile. It is not clear that it is desirable for mobile numbers to be identified as mobile numbers. Why should anyone care? /john