Phoneline to Soundcard - NEED HELP

[[email protected]]

Anyone know how-to make a cable that would plug into my telephone jack
and then into my computer soundcard?

I bought one from EBay and when I plug the cable into my phone line and
then into the soundcard my line
goes dead.

One guy mentioned he uses an isolator circuit of some sort to not short
out the line in his device.

This is the one I bought below that doesn't work.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=14960&item=5774136958&rd=1&ssPageName=WDVW

**********

This one below supposedly works with a soundcard and phoneline.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5769614109&rd=1&sspagename=STRK:MEWA:IT&rd=1


If you can help send an email to [email protected] o m

 

[Travis Jordan]

Anyone know how-to make a cable that would plug into my telephone jack
and then into my computer soundcard?

I bought one from EBay and when I plug the cable into my phone line
and then into the soundcard my line
goes dead.

The one you bought probably works fine with an ac-isolated microcassette
recorder with a high impedance microphone input.

One guy mentioned he uses an isolator circuit of some sort to not
short out the line in his device.

Yep, that would be a good idea.

Personally, I'd build such a device with a couple of .1 mfd coupling
capacitors and a 600 ohm to 600 ohm isolation transformer to provide a
balanced input. Total parts cost about $5.00. However, if you need to
buy one then....

http://www.omnicronelectronics.com/analog/LIC-100.htm

 

[DaveM]

The unit at http://www.omnicronelectronics.com/PC/LIC-1PC.htm is more
appropriate for the OP, according to his stated problem. However, if the OP
has the ability, there is a schematic of such a unit at
http://www.solorb.com/elect/phone/tap. Another one with some good details
at http://www.epanorama.net/documents/telecom/telerecord.html.
The problem with the cable he bought on Ebay is that since there is no
isolation, one side of the phone line is directly grounded to the computer
case, which will indeed kill the phone line. The phone line must stay
balanced and isolated from ground at all times, otherwise, the telco gets
mighty upset. In fact, if you leave the line in a shorted condition, they
will send a guy out to test your circuit, and if he finds the short exists
inside your house, most likely the service will be disconnected until you
remove the short. And they will charge you for the service incident.

--
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!!

 

[Travis Jordan]

The unit at http://www.omnicronelectronics.com/PC/LIC-1PC.htm is more
appropriate for the OP, according to his stated problem. However, if
the OP has the ability, there is a schematic of such a unit at
http://www.solorb.com/elect/phone/tap. Another one with some good
details at http://www.epanorama.net/documents/telecom/telerecord.html.
/analog/LIC-100.htm

The zener diodes across the transformer secondary are a good idea.

 

[Bill Jeffrey]

I've tried this (coupling to the phone line) a couple times, without
real good luck. The problem I experienced is that the outgoing audio is
MUCH louder than the incoming audio. Kinda makes sense, since the
outgoing audio will undergo line loss before it get to the other end,
whereas the incoming audio has already undergone that loss.

Question: has anyone else found this to be true? And if so, would it
make sense to take the tap at the earpiece in handset instead of across
the line? The incoming audio is present at the earpiece, of course -
and so is the outgoing audio, in the form of sidetone, which is
carefully set up to have the same apparent loudness.

BTW, if you have an old Bell phone (the hefty ones, like the 302), it is
easy to monitor it without making any connection. Simply place an audio
transformer on the case, and connect one of the windings to the mic
input of the recorder/sound card. The transformer picks up the audio
from the induction coil inside the phone. We used to do this in the old
old days, using the output transformer from any old radio. Of course it
won't work in modern lightweight phones, since they have no coil inside.

Bill

 

[Travis Jordan]

I've tried this (coupling to the phone line) a couple times, without
real good luck. The problem I experienced is that the outgoing audio
is MUCH louder than the incoming audio. Kinda makes sense, since the
outgoing audio will undergo line loss before it get to the other end,
whereas the incoming audio has already undergone that loss.

True, but with good AGC you can compensate for this.

 

[Asimov]

"Bill Jeffrey" bravely wrote to "All" (13 May 05 10:29:49)
--- on the heady topic of "Re: Phoneline to Soundcard - NEED HELP"

BJ> From: Bill Jeffrey <[email protected]>
BJ> Xref: aeinews sci.electronics.repair:48060

BJ> I've tried this (coupling to the phone line) a couple times, without
BJ> real good luck. The problem I experienced is that the outgoing audio
BJ> is MUCH louder than the incoming audio. Kinda makes sense, since the
BJ> outgoing audio will undergo line loss before it get to the other end,
BJ> whereas the incoming audio has already undergone that loss.

BJ> Question: has anyone else found this to be true? And if so, would it
BJ> make sense to take the tap at the earpiece in handset instead of
BJ> across the line? The incoming audio is present at the earpiece, of
BJ> course - and so is the outgoing audio, in the form of sidetone, which
BJ> is carefully set up to have the same apparent loudness.

BJ> BTW, if you have an old Bell phone (the hefty ones, like the 302), it
BJ> is easy to monitor it without making any connection. Simply place an
BJ> audio transformer on the case, and connect one of the windings to the
BJ> mic input of the recorder/sound card. The transformer picks up the
BJ> audio from the induction coil inside the phone. We used to do this in
BJ> the old old days, using the output transformer from any old radio. Of
BJ> course it won't work in modern lightweight phones, since they have no
BJ> coil inside.


What you need is a hybrid phone network. Basically it balances the
voice so that it has the same volume as the speaker. Older phones used
a transformer to balance the levels. New phones use an IC instead.
Another trick is to clip onto the speaker of a speaker-phone.

A*s*i*m*o*v

.... I worked hard to attach the electrodes to it.

 

[Dave Plowman (News)]

I've tried this (coupling to the phone line) a couple times, without
real good luck. The problem I experienced is that the outgoing audio is
MUCH louder than the incoming audio. Kinda makes sense, since the
outgoing audio will undergo line loss before it get to the other end,
whereas the incoming audio has already undergone that loss.

You need a TBU - telephone balance unit - to correct this properly.
They're used to connect a telephone line to a broadcast sound mixing desk
- etc. Basically, a hybrid transformer or electronic equivalent. This
convert the two wire telephone circuit to a four wire so you can adjust in
and out levels, IIRC.