From comp.dcom.telecom.tech 421 Path: ucbvax!cis.ohio-state.edu!magnus.acs.ohio-state.edu!math.ohio-state.edu!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!newsflash.concordia.ca!nstn.ns.ca!news.ucs.mun.ca!morgan!thom From: [email protected] (Thomas Clancy) Newsgroups: comp.dcom.telecom.tech Subject: Re: Phone flasher device? Message-ID: <thom.756499147@morgan> Date: 21 Dec 93 18:39:07 GMT References: <pschleck.755911955@cwis> <[email protected]> <[email protected]> <[email protected]> Sender: [email protected] (NNTP server account) Organization: Memorial University of Newfoundland Lines: 92 [email protected] (Rich Greenberg) writes: >In article <[email protected]> [email protected] (Anne Bennett) writes: >>My question is: how can I obtain a similar little box, but which, instead >>of providing its own bell, switches electricity on and off, so that I can >>use any electrical device I like (e.g. flashing light) to signal that the >>phone is ringing? >[...] >>If the best answer is to build it myself, a pointer to the needed specs >>would be appreciated. Here is a schematic that I obtained when I put the same question up some time back in a different news group. This person has used this very circuit, so it's been tested. =-) I don't remember the chaps name right off, I will see if I can find it. I don't want anyone thinking that this is my work. Give credit where credit is do. Disclaimer: I accept no responsability for whatever may happen, this text is provided for informational purposes only. ;-) ----------------------------------------------------------------- To: Thomas Clancy <[email protected]> Subject: Re: PHONE MODIFICATION QUESTION? Here it is. If you have any problems or questions let me know. #-----------#-----------------#-------------# : : : : : \ \ : : R1 / / R4 : : \ \ : : / / : : : : : ------ : : : : : +:--# \--\ : c red----:~ : Z1 /\ #------------b Q2 : B1 : -- : e : : : : : green--:~ -:--# : c : ------ : #---^^^^---------b Q1 : : : e \ : : R3 : / R5 : : : \ : : : / : : : : : \ : : : R2 / : : : \ : -- : / : \/ L1 : : : -- : : : : : : : : : : : : : : : : #-----------#-----------------#-------------# R1,R2 47000 ohms 1/4 watt R3 1000 ohms 1/4 watt R4 1000000 ohms 1/4 watt R5 6800 ohms 1/2 watt Q1,Q2 2N2222 NPN switching transistor B1 200V 1A bridge rectifier Z1 15V 1 watt Zener diode L1 red LED Notes: 1. Any NPN switching transistor could probably be substituted for Q1 and Q2, but the 2N2222 is available at Radio Shack. 2. You may need to adjust the value of R5. Make it smaller to brighten the LED (not so small that the LED burns out), but it must be large enough so that when the phone is hung-up the circuit doesn't hold the line open. 3. The phone company might have regulations about the use of 'unregistered' equipment on their lines, but if it doesn't cause any problems I don't think they really mind much. ;)