Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!netsys!vector!telecom-gateway From: dmr@csli.stanford.edu (Daniel M. Rosenberg) Newsgroups: comp.dcom.telecom Subject: How do payphones work? Message-ID: Date: 12 Jul 89 21:13:12 GMT Sender: news@vector.Dallas.TX.US Reply-To: "Daniel M. Rosenberg" Organization: Center for the Study of Language and Information, Stanford U. Lines: 15 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 233, message 5 of 9 I'm wondering about how payphones work. It seems as if there are three main types: old fortress phones, that require a coin before you can do anything. The coin "opens" the phone for you. These seem to be connected to payphone-type central office pairs. New fortress phones also seem to have special pairs (or are there four wires?) that run to the CO, but don't require a coin first. And COCOTS seem to have more regular lines, with a lot more equipment in the phone itself. What's on those two/four wires for fortress phones? How do they work? -- # Daniel M. Rosenberg // Stanford CSLI // Opinions are my own only. # dmr@csli.stanford.edu // decwrl!csli!dmr // dmr%csli@stanford.bitnet