Connecting Arduino to cell phone

Forum 2005-2010 (read only) Hardware Interfacing
1

Hello!
I have an old Siemens cellphone (who doesn't :)), model a40.
I want to connect it to Arduino to play with AT commands.
Here the pinout:

I used this:
http://tinkerlog.com/wordpress/wp-content/uploads/2008/01/beacon.png
as a reference.
Resistors R7 and R8 are connected to the 3.3v of Arduino board.

So, now comes the testing. I removed Atmega from the board to test the connection directly with FTDI (GPS datalogging shield for Arduino).
I connected TX of the phone (pin 5) to pin 1 of the arduino, and RX of the phone to 0 on arduino.
I also connected GND of the phone to GND of the arduino.

I start arduino IDE, open serial monitor and no matter what I do nothing comes out of the phone. I've sent "AT" so many times changing baud rate, switching pins on the arduino board - nothing helps.
I did the same with the GPS (removed atmega, connected to 0 and 1 pins on the board, started IDE) and it worked. With the phone it doesn't.

Is there something else I should know about serial communication with the phone? Is there a way to test rx and tx separately?

Leonti

2

Can at least someone tell me if I'm doing it right?
I've spent so much time on it already and it would be a shame just to throw it away :frowning:

Leonti

3

Don't you also need to run some software on the phone that enables the serial communication? There must be some app running on the phone that listens to the serial port, on a given baud rate.

4

Hi Leonti,

If you need, I can send the Siemens mobile's AT command list to you.

Regards,

Nadir

5

Thank you for replying!
I found another phone (Sony J5) but it's not working with it either.
So I think the problem is in my level divider.
Today I will try to use some 5v to 3.3v level converters - maybe it wil help.

Leonti