telephone receiver wanted for audio recording

I have a fair amount of technical knowledge (going back and reading my previous post it may not seem too aparent). I'm just looking for information that will point me in the right directions. knowing that telephones run on phantom power is a good start.

I also started thinking about the telephone sets used on old hotel switchboards. They were just a handset with a quarter inch handset coming out of it. would those work the same way i would need to modify a regular phone handset?

Phones are not powered by a phantom circuit.

In a phone circuit, normally a negative polarity is applied to the Ring wire and the current flows through the telephone to the Tip wire, to which the positive polarity of the power supply is connected. In a phantom circuit, current flows the same direction in both wires.

If you are just trying to use a carbon microphone and "have a fair amount of technical knowledge," wire the microphone in series with a battery (6V will do), and a resistor (200 Ohms or so). Take the signal from across the microphone, or the resistor, via a blocking capacitor. There are more elaborate methods which are more efficient, but this will give you a good start.

Carbon microphones tend to be noisy, and also the carbon granules tend to pack, reducing the conversion from sound pressure to electrical signals. A sharp rap against something solid helps improve the latter condition.

Don

I seem to have overtaxed you. Sorry about that....

Don

"anthony altomare"

** Completely false.

Telephones use a variety of mic capsules - but never "crystal".

** Depends on the particular phone but in most cases the answer is no.

Telephones are " phantom powered " - like condenser mics are - but not the same way.

Find someone technical to modify a phone handset and pick one that has a dynamic capsule.

....... Phil

Do yourself a favor, and read more on the subject.

Just so I can have a good laugh, please give me the best reference you can find to support your view that telephones are powered by a phantom circuit.

Your posts are not what I would ever call a "reference."

That is complete nonsense. Provide a reference to support this.

Yes, when done correctly, that is a phantom circuit.

You are describing a simplex power arrangement.

Yes, so what? That is not a phantom configuration.

Look, jackass, if you can't find a good reference, just say so. I suspect that you are the type of person who increasingly raises the volume of his voice as replacement for a good argument.

You aren't worth the effort to continue this. Post what you will, but I will not respond to you on this topic.

This article

explains what you need to do to interface a standard analog telephone to your sound card. You simply require a transmitter power supply (9V battery) which is isolated from the sound card, (hence the transformer).

I have noticed when accessing the link via my post you don't see the full Silicon Chip article, unless you are prepared to pay to see the rest of it, that is. If you type 'voip phone adaptor silicon chip' into Google you will get the full article for free. At least, it does for me.

Strictly speaking Phil, a POTS instrument is not phantom powered, although I can see why it would fit that description under your broad definition.

If we go back to the earliest central battery telephone instruments you will recall that they used a carbon granule microphone. The idea is that the DC line current flows through the microphone which in turn varies its resistance proportionate to the sound pressure waves on the diaphragm thereby varying the line current. Thus, the microphone simply modulates the line current which is then passed through a transformer in the exchange line interface circuit to derive the AC speech signal for transmission over the network.

While modern telephone instruments no longer use a carbon granule microphone (although telephones employing them will still work today), the IC in these instruments must duplicate exactly what the old carbon microphone did, ie. modulate the DC line current. The fact that the IC derives its minute operating power from the line voltage may qualify a modern telephone as being phantom powered under your broad definition, but this fact is secondary only to the operation of the telephone, and in my opinion doesn't truly fill the bill. Phantom powering devices in telephony always relied upon the use of centre-tapped signal transformers such as the venerable 4012A.

"Don Bowey"

** Of course they are - you dimwit. ** Phantom powering refers to any circuit where the power to operate the device is fed along the same wires used for signals to or from the device.

Condenser mics used a 3 wire, balanced circuit with the DC phantom delivered in common mode.

A mast head RF amplifier uses the coaxial feeder cable to supply it with AC or DC power from a remote supply.

** Better not overtax the OP - he is still trying to figure out what crystal mic is.

........... Phil

"Don Bowey"

** The only thing you are overtaxing is your c*ck.

........ Phil

"Don Bowey"

** Try reading what was posted already:

" Phantom powering refers to any circuit where the power to operate the device is fed along the same wires used for signals to or from the device.

Condenser mics used a 3 wire, balanced circuit with the DC phantom delivered in common mode.

A mast head RF amplifier uses the coaxial feeder cable to supply it with AC or DC power from a remote supply. "

** Do you laugh like a hyena or a jackass ?

** Does DC current pass down the signal wires to power the phone ?

......... Phil

"Don Bowey"

** Piss off - you pathetic troll.

......... Phil