Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!uwm.edu!linac!att!pacbell.com!lll-winken!telecom-request From: rcj1@ihlpf.att.com (Raymond C Jender) Newsgroups: comp.dcom.telecom Subject: Re: Questions About New Service Being Installed Message-ID: Date: 29 Mar 91 05:23:09 GMT Sender: Telecom@eecs.nwu.edu Organization: AT&T Bell Laboratories Lines: 23 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 251, Message 7 of 11 In article , drears@pica.army.mil (Dennis G. Rears (FSAC)) writes: > What I'd like to know is what are 2 and 3ESS? What's the difference > between a 1 and a 1A (is it just the processor? Does 1A run Unix?) > And what kind of hardware does a 4ESS have (I've never seen one)? The 2 and 3ESS are smaller rural type switches. Sorry, I don't know much more then that without researching. The 1 and 1A differ in the processor used. The 1E uses an analog processor. The 1A Processor is digital. Both 1E and 1A use the same network, thus when a 1E is being retrofitted to 1A, only the processor is swapped out. That the reason that the calls sound exactly the same on both switches, they only complete quicker. No, the 1A does not run Unix, or any other popular brand of OS. It uses it's own proprietary and unique assembly language. The 4E uses the 1A processor. It's network is digital. It can be used as either a Toll or Tandem switch. I guess you can say there was a completely digital switch being used back in, oh, when did the first 4E cut over, 1975-78 time frame?