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recording the phone

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Thunderchild

New Member
how cn I record from the phone is there a cheap kit or is it simply done my main query is how exactly do I interface with the phone line its 40 volts isn't it but i thunk drops to 8 when you pick ok but that means i can blow my circuit when I hang up again
 

dknguyen

Well-Known Member
Most Helpful Member
Thunderchild said:
how cn I record from the phone is there a cheap kit or is it simply done my main query is how exactly do I interface with the phone line its 40 volts isn't it but i thunk drops to 8 when you pick ok but that means i can blow my circuit when I hang up again

Can't you just buy a suction cup microphone and stick it on the phone? I saw on at Radio Shack the other day.
 

audioguru

Well-Known Member
Most Helpful Member
An old fashioned phone and a new one that is "hearing aid compatible" produces a magnetic field of the distant caller, but not what you are saying. So you can use a suction cup coil (not a microphone) to record them but not you.

If you connect something to the telephone line then it will probably cause loud hum on the line. The 90VAC ringing signal would probably kill your circuit if it connects directly to the phone line.
 

Dean Huster

Well-Known Member
Actually, I think you'll record both. Part of the audio from your end is sent to the earpiece. That's why it's often so difficult to hear the caller when there's a high ambient noise around you.

The pickup can be homemade by wrapping a few hundred turns of fine wire around a bar magnet and feeding the output of this coil to the input of your recorder. Hold one pole of the magnet near the phone receiver to pick up the audio. New phones that may not have an electromagnetic earpiece like the old Ma Bell phones of yore may not work in the application.

Dean
 

DigiTan

New Member
This is the setup I use. The black phone has an inductive pick-up coil like the kind they sell at Radio Shack. This one's glued onto the ear piece. It operates completely through the field induced by the speaker, so no assembly required.

The cord plugs straight into the tape recorder with one of those 3.5mm mic jacks. I've had it for months and the audio quality is pretty great on both sides of the conversation. Depending on your local laws, you might find them at any electronics retailer.

**broken link removed**
 
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crusty

New Member
couldn't you tap off directly off the earpiece lines? It would probably give you around a line level output. I know ramsey makes a pretty decent kit for plugging directly to the phone line, gives you option of RCA output, and mixer.
**broken link removed**
If you want to get an idea of just the phone patch section of it, you can look at their schematic for it.
https://www.ramseyelectronics.com/downloads/manuals/PPM3C.pdf
 
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Thunderchild

New Member
clever guy ramsey he gives all the theory (I think did't read all the pdf) but dosen't give a scematic hm.
all I need is to record to a tape or the computer nothing crazy like putting it on air
 

DigiTan

New Member
The pickup coils only go for ₤4.99 on Maplin. Are you trying to record from a handset or actually splice the line?
 

mvs sarma

Well-Known Member
The concept followed by Digitan is correct. many times we find that the Receiver module is encapsulated in a aluminiun container . as such, placement of coil mat not work equally for all instruments.

the access at the receiver point can bee the best. If the receiver is dynamic type,if possible the connections the Rx may be tapped and connected to an isolation transformer. the output can be scaled down and applied to the recoding device. If the receiving elemenet is pezio type we have to have a proper buffer becfore we could pick up.

Some telecom adminstrations object tampering of the tlecom line or the instrument.
 
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