If you have a USB console cable you can wire it up directly and send commands using any Terminal software

For Windows, we suggest Putty - it's free and open source!

Wire it up

In this example, we're using our USB console cable.
You will have to install the PL2303 driver and determine the COM port before you continue.
Connect to that COM port at 8N1 (8-bit, no parity bit, 1 stop bit) at 9600 baud. You can actually use any baud rate and it will autodetect but 9600 is supported by any terminal program!

Double Check!

  1. You have a Lipoly battery plugged in to the FONA JST
  2. You have a working 2G SIM installed in the back
  3. Connect Black wire to GND
  4. Connect White wire to TX
  5. Connect Green wire to RX
  6. Connect Red wire to Vio
  7. You may need to hold down the KEY button for 2 seconds until the PWR LED is lit and the NET LED blinks

Test Commands

The FONA will echo characters back so you can see what you're typing - very handy!

Start by initializing the auto-baud'er by sending AT and then return
You may have to try it twice to get it to auto baud. Once it works you should see the AT characters echo and then OK telling you its OK!

You can then send some commands to query the module and get information about it such as
ATI - Get the module name and revision
AT+CMEE=2 - Turn on verbose errors (handy for when you are trying out commands!)
AT+CCID - get the SIM card number - this tests that the SIM card is found OK and you can verify the number is written on the card

Test Setup

Some tests to verify the setup

  • AT+COPS? Check that you're connected to the network, in this case T-Mobile
  • AT+CSQ - Check the 'signal strength' - the first # is dB strength, it should be higher than around 5. Higher is better. Of course it depends on your antenna and location!
  • AT+CBC - will return the lipo battery state. The second number is the % full (in this case its 92%) and the third number is the actual voltage in mV (in this case, 3.877 V)
If your SIM card is locked with a PIN code, you will need to enter the pin before you can connect to a network via the 'AT+CPIN' command. For example if the pin is 1234 you need to enter 'AT+CPIN=1234".

Test Send SMS

Finally, you can try to text your phone! Sending an SMS is pretty darn easy.

  • AT+CMGF=1 - this will set it to TEXT mode not PDU (data) mode. You must do this because otherwise you cannot just type out the message.
  • AT+CMGS="nnnnnn" - send a text message! You will get a '>' prompt for typing. Type out your message and when you are done send a [Control-Z] on an empty line to send
It may take a few seconds after the Control-Z character for the module to send the SMS (you'll get a +CMGS) and verify it was sent (OK reply)

Test Call

You can also make a phone call, you must have a headset attached to the 4-pole 3.5mm headset connector, with a mic!

To call, dial
  • To call, dial ATDnnnnn; Don't forget the ; at the end!
  • If they pick up you'll hear it in the headset, if no pickup, you'll get a NO CARRIER return
  • Once you are chatting, you can hang up by sending ATH

This guide was first published on Jul 02, 2014. It was last updated on Feb 10, 2016.

This page (Wiring to USB) was last updated on Jun 27, 2014.

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