I'm new to the Arduino scene and need some help reading data from a RJ11 socket as shown below.
Firstly i'm not sure if this data should be read as Analog or Digital
I'm basically interested in reading data from the the TD pin (2), but i'm not sure how this should be wired to the Arduino.
Do i basically wire Pin 2 form the RJ11 to pin 0 (Rx Pin) on the arduino and then wire one of the GND pins from RJ11 to GND on the Arduino.
Also, the power souce of the RJ11 seems to be +12v, so when reading the input do i need to take precautions or will Pin2 on the RJ11 not have 12v running through it.
First of all, remember this isn't a 24 hour customer service hotline; patience, friend!
The RJ11 is just a type of connector used for wiring. It has six wires in it. (It is typically used in telephone cables. There are many other kinds also.) How you use it depends on what it is connected to and what data is being transmitted over it. That will determine the programming you need.
But, you can get connectors (like this one) which you can put on a circuit board, with the pins connected to Arduino pins and then transmit/receive data over the cable.
If you can be more specific about your application, you will probably get more of a response.
I'm trying to read data which from a telescope controller handset, and the rj11 on the handset is used to connect to a pc via RS232 (serial) port.
I've trying to discover what data is being is being transmitted through the RJ11, so i dont know the data type.
I simply want to know which pin should be used on the Arduino for reading data from the Tx pin on a serial cable. Should i use the Pin 0 Rx on The arduino or just any other pin as long as i define it in my code ?
If it's true rs232 you'll need an interface like the MAX232 between the device and the arduino. (I'm assuming you have a standard USB arduino; if you have a serial arduino with a DB9 this wouldn't be needed).
You're hung up on the RJ11 - forget it for a minute and think about the electrical part of the interface. That's what is important; the mechanical part is just connecting wires. The mechanical part of the connection doesn't automatically tell you anything about the electrical part, especially when it's a non-standard connector like this.
For the mechanical connection, you can get an RJ to DB9 shell to adapt the connection to a standard DB9 (e.g. to connect to a serial arduino), or just get a female-female telephone adapter (used for extending phone lines) and get a phone cable and chop one end off it.
So seeing there is 0v between TD & GND is it likely to be safe to try and connect it to the Arduino ?
No,because you don't yet know the opposite state of the signal. A digital signal has a high and low value, you have just one measured one possible state. You really need to find a more detailed document the defines the interface, or possibly check around some telescope forums to see if anyone knows what's what. What is the brand and model of the scope?
Since the diagram maps to a standard DB9, the signals are likely RS232 voltages and levels, and you will need a level conversion circuit such as a MAX232.
Thanks guys, i'll look into getting a Max232 chip or maybe a Arduino serial shield if they exist.
Probably almost as cheap, why don't you consider a Arduino clone that interfaces using a real RS-232 serial port. He is one that I bought that works great. I assembled it about an hour, all easy to solder through hole components: