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: thom@morgan.ucs.mun.ca (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> <1993Dec14.235905.28344@news.yale.edu> <CI3Bx6.Js8@newsflash.concordia.ca> <richgrCI3x57.HKB@netcom.com>
Sender: usenet@news.ucs.mun.ca (NNTP server account)
Organization: Memorial University of Newfoundland
Lines: 92
richgr@netcom.com (Rich Greenberg) writes:
>In article <CI3Bx6.Js8@newsflash.concordia.ca> anne@alcor.concordia.ca (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 <thom@morgan.ucs.mun.ca>
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. ;)