bwhite@oucsace.cs.OHIOU.EDU (Bill White) (06/01/90)
In article <1990May22.151642.18729@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: > >You will also need to sign up for Caller ID, and pay whatever monthly fee >the local phone company feels like charging for it. Assuming, that is, >that it's available in your area. Stories claiming that (a) it is available >everywhere, and/or (b) it is available free, are just that: stories. Old >switching gear can't do it at all, and you better believe the phone company >wants money for it. I've heard (from several people) of "homebrew" caller-ID boxes that worked entirely by themselves, ie no phone company modifications were needed. I seem to recall that they had something to do with sending certain frequencies. Or is this a myth? If so, it's a very persistent one. Also, does anyone know what the fourth wire in standard telephone hookups is for? -- | Bill White Internet: bwhite@oucsace.cs.ohiou.edu | | BUCY'S LAW: | | Nothing is ever accomplished by a reasonable man. |
bill@videovax.tv.tek.com (William K. McFadden) (06/07/90)
In article <1417@oucsace.cs.OHIOU.EDU> bwhite@oucsace.cs.OHIOU.EDU (Bill White) writes: > I've heard (from several people) of "homebrew" caller-ID boxes that >worked entirely by themselves, ie no phone company modifications were >needed. I seem to recall that they had something to do with sending >certain frequencies. Or is this a myth? If so, it's a very persistent one. I believe modem-like tones are sent between the first and second ring to identify the caller. Several third parties offer decoder boxes. For more information, subscribe to comp.dcom.telecom. > Also, does anyone know what the fourth wire in standard telephone >hookups is for? Tip & ring are the red & green wires (I keep forgetting which is which). These carry the loop to the phone company. Yellow is ground, and is connected to a safety ground on the premises (primarily for lightning protection). The black wire, I've been told, is used to supply power to dial lights in phones that have them. The power comes from a small doorbell-like transformer the phone company installs in your house. If any of this is wrong, I'm sure I'll be corrected. -- Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077 bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill Phone: (503) 627-6920 "The biggest difference between developing a missle component and a toy is the 'cost constraint.'" -- John Anderson, Engineer, TI