"Line in use light"

[Bill Johnson]

Hi, I hope I'm not posting to the wrong group.

I have a pretty standard touchtone desk phone and want to install a small
LED light the would come on whenever anyone is on one of the other phones in
the house.

What resources are there available so I can do this on the cheap??

Please respond by email if necessary.

81162@sbcglobal.net

Thanks, Bill Johnson

 

Bill Johnson <81162@sbcglobal.net> wrote:

Hi, I hope I'm not posting to the wrong group.

It's OK, but sci.electronics.design might be a little better -
cross-posted and followups set.

I have a pretty standard touchtone desk phone and want to install a small
LED light the would come on whenever anyone is on one of the other phones
in the house.

There are several circuits to do this at
http://www.repairfaq.org/ELE/F_ASCII_Schem_Tel.html .

Matt Roberds

 

[DaveM]

"Bill Johnson" <81162@sbcglobal.net> wrote in message
news:OpaKe.3655$zr1.2903@newssvr13.news.prodigy.com...

Hi, I hope I'm not posting to the wrong group.

I have a pretty standard touchtone desk phone and want to install a small
LED light the would come on whenever anyone is on one of the other phones
in
the house.

What resources are there available so I can do this on the cheap??

Please respond by email if necessary.

81162@sbcglobal.net

Thanks, Bill Johnson


..

http://www.discovercircuits.com/PDF-FILES/1phostat.pdf

--
Dave M
MasonDG44 at comcast dot net (Just subsitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!

 

[Watson A.Name - \"Watt Su]

"DaveM" <masondg4499@comcast99.net> wrote in message
news:Lq2dncsh0Is09WTfRVn-rw@comcast.com...

"Bill Johnson" <81162@sbcglobal.net> wrote in message
news:OpaKe.3655$zr1.2903@newssvr13.news.prodigy.com...
Hi, I hope I'm not posting to the wrong group.

I have a pretty standard touchtone desk phone and want to install a
small
LED light the would come on whenever anyone is on one of the other
phones
in
the house.

What resources are there available so I can do this on the cheap??

Please respond by email if necessary.

81162@sbcglobal.net

Thanks, Bill Johnson


.
http://www.discovercircuits.com/PDF-FILES/1phostat.pdf

--

The good thing about this circuit is that it flashes, so it draws
attenion to the LED. The bad thing about it is that it uses a CMOS
part, which is susceptible to being zapped by lightning. It should have
a .02uF bypass capacitor from pin5 to ground to reduce the possibility
of a transient voltage spike zapping the chip. But it is still
susceptible. So buy a few spare chips and use a socket, and when it
gets zapped and quits working, just replace the chip. ;-)