Plain Old Telephone Service (POTS)

Hi, I’m new to Audino and would appreciate some advice. I am working on a prototype communication project that requires an old school (two wire) phone as an input/output device for an Audino board.

I am comfortable with the coding, if I can get an analogue input/output to the Audino. I am planning on using a 9v cell to power the phone loop but I need a way of converting this to 3.3v.

Sorry if all this sounds really basic but I have no experience with constructing hardware and any help would be welcomed.


POTS use quite high voltages 50(?) volts or more. And arduino can only handle 0-5V so be careful. For the rest it is not clear what the goal is and the question. So tell us ....

I don't think there is a question...

One more in the dust bin. :grin:

For legal and compliance issues, at least here in the US, attaching equipment to the POTS system requires the use of an approved DAA (data access arrangement) module. This protects the POTS from 'foreign' voltages and grounds. These usually also handle the voltage translation needed to interface to logic systems like the Arduino.



Thank you for the info, I can see that the question was a bit vague, so let me start over.

I would like to use an old telephone as an input / output device connected to an Arduino board, I am not going to connect to the telephone system.

My question is, how do I connect the phone to the Arduino, in a way that when I speak into phone I get an analogue signal (at a low voltage) input to the Arduino? And visa versa (analogue output to phone speaker)?

There is lots of info out there...

It's just a microphone...