neumann@udel.edu (Brian R. Neumann) (12/18/89)
Does anyone know of any simple circuit I could build or of any device
that I could by to show when the phone is in use? A small LED would
be helpful -- I'm getting tired of the family picking up the phone while
I'm using the line for the computer. I haven't seen anything like this
available. It sounds simple to me, but that doesn't necessarily mean
it is.
--
_ _ _
|] |] | |_| |\ | |\ | |_ | | |\/| |_| |\ | |\ | Neumann@louie.udel.edu
|] |\ | | | | \| | \| |_ |_| | | | | | \| | \| Neumann@vax1.udel.educ37189h@saha.hut.fi (Harri Olavi Suomalainen) (12/18/89)
In sci.electronics neumann@udel.edu (Brian R. Neumann) writes: > >Does anyone know of any simple circuit I could build or of any device >that I could by to show when the phone is in use? Voltage on the line is ~60 volts when line is free and ~10 volts while the line is on use. You could bild up a simple device with only a few transistors, fets etc. Notice that while the phone is ringing there is ~120VAC on the line! Be sure your circuit can take that! Notice that you'll need an external power supply (eg. a battery) to power your led. In case you'd take that "much" current from the line your central office would find your line to be in use as if you'd picked up a phone! Chears, Harri Suomalainen -- If you're feeling good, don't worry: you'll get over it ! c37189h@saha.hut.fi haba@otax.tky.hut.fi
deanr@sco.COM (Dean Reece) (12/20/89)
In sci.electronics neumann@udel.edu (Brian R. Neumann) writes: > >Does anyone know of any simple circuit I could build or of any device >that I could by to show when the phone is in use? Sure, I built one into my phone, and it works great. The schematic is available on page 668 of "The GIANT Handbook pf Electronic Circuits" published by TAB books, ISBN= 0-8306-9673-3 in hardback, or ...-9662-8 in paperback It needs a 6 volt (or 5 volt) external supply. ______________________________________________________________________ | Dean Reece Member Technical Staff |"The flames are all long gone | | The Santa Cruz Operation 408/458-1422 | but the pain lingers on" | |___________deanr@sco.com_______________|___________________Pink_Floyd_|
jim@mmsac.UUCP (Jim Lips Earl) (12/20/89)
You might want to pick up the December issue (if still available) of POPULAR
ELECTRONICS/HANDS ON ELECTRONICS. It had an article/schematic of a circuit
that contained only a couple of parts. You have to put one on every phone
in the house, but it will do what you want. It has no LED, but if someone
is on the line, it "locks out" all the rest of the phones in the house.
It requires no additional wires to be run to each phone. If you can't find
the issue, I'll try and do an ascii schematic for you.
--
Jim "Lips" Earl UUCP: ucbvax!ucdavis!csusac!mmsac!jim
KB6KCP INTERNET: mmsac!jim@csusac.csus.edu
=======================================================================
The opinions stated herein are all mine.deanr@sco.COM (Dean Reece) (12/20/89)
In article <4174@scolex.sco.COM> I write: > >In sci.electronics neumann@udel.edu (Brian R. Neumann) writes: >> >>Does anyone know of any simple circuit I could build or of any device >>that I could by to show when the phone is in use? > >Sure, I built one into my phone, and it works great. The schematic is >available on page 668 of "The GIANT Handbook pf Electronic Circuits" >published by TAB books, ISBN= 0-8306-9673-3 in hardback, or ...-9662-8 >in paperback > >It needs a 6 volt (or 5 volt) external supply. I meant that the circuit needs 5 volts, not the book :-) Anyway, I thought I would try to post the schematic. The branch of the circuit that contains C1, C2 & R5, R6 is only used as a passive tap. (So you can record the line when the rest of the circuit says 'off hook'. It can be removed if not needed. If used, it can directly drive a microphone input to a portable recoreder. The Output of Q2 completes a path to ground when the phone lines gives an off hook reading. This can drive a relay (for a tape recorder motor) or an LED. Be sure to include a current limiting resistor if an LED is used. Also, D1 may be ommited if a non-inductive load is used (Relays and incandescent (sp?) lamps are inductive) The LED thingy like this that I made for my phone flashes nicely when the phone rings (at the 20..25 Hz ring freq), so I can turn the ringer off, and still get silent ring indication (a feature, not a bug) Well, its not exactly postscript(tm), but if you stand back and squint, you'll get the idea. R5 <----+^v+ +----------+--------* +6vdc (I use 5 volts) R6> | | D1_ < | R3> ^ ___ <----+ | < +--------> Out | | | R8 Q2|/ C1=C2= +-^v-+---| | | R1 BR1__ Q1|/ | |\v *----+------v^---| |--+--+---| R4> | | |~+|R7<C3L |\v < | | R2 |~-| > T | | | *-------+---v^---|__|--+--+-----+----+-----+--------* Ground |_ /// R1, R2 2.2M Reproduced (kind of) without R3, R4 470K permission. Copyright 1980 R5 470 TAB BOOKS Inc. R6 100 R7 100K R8 220K C1, C2 0.01uf, 100V C3 1.0 uf BR1 Full wave Bridge Rectifier, about 200 VDC (or higher) D1 HEP R0052 (I use 1N400*) Q1, Q1 HEP S9100 -or- NTE-172a ______________________________________________________________________ | Dean Reece Member Technical Staff |"The flames are all long gone | | The Santa Cruz Operation 408/458-1422 | but the pain lingers on" | |___________deanr@sco.com_______________|___________________Pink_Floyd_|
jim@mmsac.UUCP (Jim Lips Earl) (12/22/89)
In article <6375@nigel.udel.EDU>, neumann@udel.edu (Brian R. Neumann) writes: > > Does anyone know of any simple circuit I could build or of any device > that I could by to show when the phone is in use? A small LED would > be helpful -- I'm getting tired of the family picking up the phone while > I'm using the line for the computer. I haven't seen anything like this > available. It sounds simple to me, but that doesn't necessarily mean > it is. > -- I got a lot of mail requesting this schematic. So here it is, best I could do, ascii-wise. This is from Popular Electronics, Dec.89 issue, by TERRANCE KELLY. It's called THE EXTENSION SILENCER. Here is what it does: you place the following circuit in series with EACH telephone that is hooked to your incoming phone line. All phones will ring normally, and the first one to answer locks out the others. Someone picking up an extension will hear nothing if the line is already in use. If you need to switch extensions all you have to do is pick up one extension and hang up the other. phone - <--------------------------------------------------------> red line + <----| | 1-amp, 50-PIV triac to | phone | | /| ----- | MT1 |/ | MT2 |_____________________|\ |__________________________> green | /| \| | | G / | /| | | / |/ | | | | 15v zener| | | \ 1N4744 | | 1k | | /| | |------/\/\/------|----------|< |-------| | \| \ If you have trouble making the thing work, try swapping the +/- leads coming into the circuit from the phone line. -- Jim "Lips" Earl UUCP: ucbvax!ucdavis!csusac!mmsac!jim KB6KCP INTERNET: mmsac!jim@csusac.csus.edu ======================================================================= The opinions stated herein are all mine.
zeeff@b-tech.ann-arbor.mi.us (Jon Zeeff) (12/27/89)
You can buy these devices if you don't want to make one. Usually called a "phone stopper" and is sold for use with answering machines. They work well. About $10. -- Jon Zeeff zeeff@b-tech.ann-arbor.mi.us or b-tech!zeeff
jim@mmsac.UUCP (Jim Lips Earl) (12/29/89)
Jon Zeeff says: > You can buy these devices if you don't want to make one. Usually called > a "phone stopper" and is sold for use with answering machines. They work > well. About $10. Remember that you need one of these devices for *each* phone on the line. So if you have 3 phones, we are talking $30 here. On the other hand, if you have a soldering iron and some solder, you can build them for about $3 apiece. $9 vs. $30 sounds pretty appealing to me. -- Jim "Lips" Earl UUCP: ucbvax!ucdavis!csusac!mmsac!jim KB6KCP INTERNET: mmsac!jim@csusac.csus.edu ======================================================================= The opinions stated herein are all mine.
dav@eleazar.dartmouth.edu (William David Haas) (12/30/89)
On a simular but different note, does anyone know how to wire two phone lines into a USOC:RJ14C jack? It allows you to have two lines connected to one phone (special phone) through one phone cord.