---------------------------------------------------------------------- Message-ID: <4899aa5259e1aa7f38046010944f313c.squirrel@email.fatcow.com> Date: Sat, 20 Aug 2016 00:24:32 -0500 From: "Neal McLain" <nmclain.remove-this@and-this-too.annsgarden.com> Subject: Re: Old London Telephone Exchange Names On Friday, August 19, 2016 at 9:11:51 AM UTC-5, HAncock4 wrote: [snip] > In the 1950s, many small towns could have any number of > digits. With the coming of Direct Distance Dialing, every > local phone number had to get expanded to seven unique digits, > with a unique exchange code within the area code. Sometimes > it just meant padding a two or three digit number with zeros, > but other times it meant new numbers. My favorite example of leading zeroes would be Nelson, Nevada, an unincorporated community in Clark County south of Las Vegas. Google calls it "Nelson Ghost Town". According to Wikipedia the population is 37. The Census Bureau recognizes it as a "census-designated place" (presumably so they can count those 37 residents). But Nelson has its own NPA-NXX thousand-number block: 702-291-0xxx. When I visited there back in the 90s, all Nelson phone numbers were in the range 702-291-00xx. A grand total of 100 possible numbers! > Since all dial exchanges back then was electro-mechanical, it meant > a great deal of new equipment and re-wiring. All of this was just > to handle _incoming_ toll calls. Most of the "electro-mechanical" equipment was some variation of Almon Brown Strowger's "up-and-around" switch, extensively utilized by GenTel and the Bell System during the 50s and 60s. https://en.wikipedia.org/wiki/Strowger_switch With the introduction of nationwide toll dialing it was necessary for each exchange to utilize 7-digit directory numbers. An older 3-, 4-, 5-, or 6-digit Strowger exchange would be modified to accept inbound 7-digit numbers by adding "dummy" leading digits. For local calls the dummy digits were ignored ("absorbed") at the first selector by digit absorbers. I have written about absorbers in previous T-D posts: https://groups.google.com/d/msg/comp.dcom.telecom/hUBAP8WzrNc/QYbcLVxHavMJ https://groups.google.com/d/msg/comp.dcom.telecom/eRvBdpAU62w/oNhgyqO1EXEJ Neal McLain ------------------------------ ********************************************* End of telecom Digest Mon, 22 Aug 2016