Path: utzoo!attcan!uunet!pyrdc!netsys!vector!nobody From: ucla-an!bongo!julian@ee.UCLA.EDU (julian macassey) Newsgroups: comp.dcom.telecom Subject: (none) Message-ID: Date: 9 Nov 88 10:11:08 GMT Sender: chip@vector.UUCP Lines: 54 Approved: telecom-request@vector.uucp X-Submissions-To: telecom@bu-cs.bu.edu (TELECOM Digest Coordinator) X-Administrivia-To: telecom-request@vector.uucp (USENET Telecom Moderator) X-TELECOM-Digest: volume 8, issue 175, message 1 There has been a fair amount of discussion about what you will find on the second pair of phone wires in a residence. Here is a list of what you might/could find: The first pair will always carry a regular phone line. These wires are usually Red and Green, they can be White with a Blue Stripe and Blue with a White stripe. They are referred to as Tip and Ring. The Green or White/Blue wire is Tip and the Red or Blue/White is Ring. Tip is Positive and Ring is negative. ( Yes I know the voltage thingy is more complex than that, this is not for experts. For folks with Rat Shack meters, what I have said is true) Ok, now the first pair is out of the way, let's look at the second pair. They are usually Black and Yellow or White/Orange and Orange/White. These wires can have several things happening to them, but not all at once. First of all, there can be nothing on the wires, and they may not be connected anywhere. Next, the Yellow wire can be grounded. This is rare these days, but you will find it on old installations. Another old thing you will find is AC voltage for lighting the dials of old Princess phones. If you look around, you will find a wall transformer wired into the Yellow and Black wires. If the transformer says, "Bell System Property" etc. That's it. If you no longer have a rotary dial Princess with a lighted dial, pull it. Talking of old, old style multiline "business" phones. Yes, the ones with the buttons that light up and flash, they needed a hard wire signal to know that a line was off hook. This was known in "Telco speak" as "A-Lead control". If a single line phone was used as an extension on one of these systems also known in "Telco speak" as "1A2", the second pair (Yellow and Black) were shorted together when the phone went "off hook" to let the system know that a line was in use so all the right blinky lights came on. If you used a phone without A-Lead control, it went into hold when you hung up - most inconvenient. These days, if the telco uses the second pair, it is usually for a second line. Looking back to the first paragraph, the Black wire is Tip and the Yellow wire is Ring, usually known as Tip 2 and Ring 2. Yup, that makes the first pair (Red&Green) Tip 1 and Ring 1. Now, when discussing PBXs and modern "Key Systems", the second pair can often carry "data", stuff controlling the phones. Hope this helps. Yours Julian Macassey Why should we let the Government do anything? They can't even deliver the mail.