In article <1993Jan10.063830.1164@athena.mit.edu>, cthomas@athena.mit.edu
(Michael T Ford) wrote:
>
> In article <1io3i5INNnat@MINERVA.CIS.YALE.EDU> shaffer-wendy@MINERVA.CIS.YALE.EDU (Wendy Shaffer) writes:
> >Regarding the telephone in use light, the Feb issue of Popular Electronics has
> >a schematic. Unfortunately, I'm completely unfamiliar with how the telephone lines
> >work.
> >The schematic shows two wires going to the telephone line. One of them is marked with the word "Tip" and a + sign. The other is marked with "Ring" and
> >a minus sign. Could somebody fill me in on what these mean and how to identify
> >one from the other. Thanks
>
> Telephones nowadays run off of only two conductors. The red and green
> wires are the most common. And if I remember correctly, red is tip, and
> green is ring. (Someone correct me if this is backwards.)
> Don't worry about hooking the circuit up backwards; the worst that will
> happen, if anything, is that it won't work.
>
> Good luck,
> Mike WZ0C
Installers often pay little attention to polarity when installing
residential wiring. You may find tip or ring on any color wire in the
outlet. Many installations (particularly newer ones) use more pairs anyway
which do not necessarily include red and green!
I haven't seen the circuit mentioned, but a good design would include a
polarity guard (all electronic telephones do) so that the connection
