phone call cable!

anybody ever hacked a RJ-45 4 pin socket?
can't find a datascheet.

I'm trying to listening to my voice on the monitor as analog in...
my voice talking to the phone.
any help appreciated.

I think it's called an RJ-11. Have a look at this

You don't want to connect directly to a phone line - the ringer voltage will fry your Arduino.

Here is a link to a Nuts and Volts article with a schematic on how to connect a Basic Stamp to the phone line.

I built it and it works fine for DTMF dialing - not sure if it will give you the audio signal you need.


Phone systems use the presence of a load on the line to determine when to go off
hook and present a dial tone to local phone or other equipment and a busy signal
to others trying to dial in.

The phone line carries more than just audio signals; a direct-current (dc) supply
voltage, a high alternating-current (ac) ringing voltage, and dangerous voltage
spikes all show up on the phone lines.

Despite its rugged signals, the Federal Communications Commission (FCC)
considers the phone system to be tender as a newborn babe. They insist that their
baby be protected from voltages that might confuse or hurt it.

For all those reasons, you need an interface to connect anything, including the BS2, to the
phone line. If you're manufacturing a product, the FCC requires that you use an approved
Data Access Arrangement (DAA).

The 4-pin handset connector is here.

Note that, even though they're customarily wired with only 4 conductors (sometimes even 2, since those are the only ones used for a single phone line), the plugs and jacks used to hook a phone to the network are actually 6-pin connectors.


thaks a lot
I'll tell if I can link it up to arduino (probably tonight / tomorow)

grazie mille

Ron c, the project of wiring the basic stamp do the phone network is really cool.
I'm just trying to listen to the phone as analog in, just like as it was a piezo buzzer.
It works (almost) good with piezo.
I feel it's not my voice what is running on the serial monitor.

thanks to ran for the schematics, now it can be botha resistance problem or a voltage problem.

I'll keep on trying.