larry@kitty.UUCP (Larry Lippman) (10/08/86)
In article <564@nbifet.UUCP>, harlan@nbifet.UUCP (Harlan Olson) writes: > Has anyone successfully wired a small light to a telephone so that it will > illuminate when it rings. Here is a simple circuit which can be built for less than $ 3.00 in parts: TELEPHONE LINE T (GREEN) __________/\/\/\/\/\__________| |_____ 33,000 ohms | | | 1/2 WATT 0.22 uF | 200 WVDC | _____________ | TELEPHONE LINE R (RED) _______| NEON LAMP |_________________| |___________| NE-51 NEON LAMP IN HOLDER This circuit consists of a resistor, capacitor, and neon lamp, all in series. Use care in assembly so that all circuit wiring remains insulated from the case and environment. This circuit is NOT intended for use on party lines. > Is it legal? This circuit meets all certification requirements for FCC Part 68 in that: (1) there is no external ground connection, so that longitudinal balance is unaffected; (2) there is no external voltage nor other signal applied to the telephone line; (3) there is no DC current draw from the telephone line; and (4) "ringer equivalence" is less than 1.0. However, technically, you have not OBTAINED certification for the circuit (unless you want to sent it to the FCC :-) ). But for all intents and purposes, provided that it is built according to the above directions, this circuit will cause no interference with telephone usage, and certainly cause no harm to the "network" (the BIG network :-) ). ==> Larry Lippman @ Recognition Research Corp., Clarence, New York ==> UUCP: {allegra|decvax|rocksanne|rocksvax|watmath}!sunybcs!kitty!larry ==> VOICE: 716/688-1231 {hplabs|ihnp4|seismo|utzoo}!/ ==> FAX: 716/741-9635 {G1,G2,G3} "Have you hugged your cat today?"