I have just received a Simcon A6760E Breakout. It responds okay to AT commands. With a GiffGaff PAYG Sim, previously used in a phone , antennas fitted and 5 volts connected I get the fast flashing green led hich I believe indicates that it is not connecting to a network. Do I need to add the GiffGaff SMSC address, +447802002506, using an AT command? I would have thought the Sim would have this from its previous use in a phone. If I am missing anything else please let me know. Thanks - John
Show a wiring diagram, including power supply, and your sketch. Have you read other A7670 threads?
I hve not got as far as connecting the Arduino. I am still trying to get it respond consistantly to AT command via USB. It is very inconsistant sometimes AT commands give the expected result and othertime I get ERROR. At times the green led flashes and other times it doesn't. I have established that SIM has got a SMSC address. AT+CSQ give +CSQ 23,99 which I believe is a good signal. The SSCOM3.2 Termial also frequently locks up. I have the SIMCOM driver installed.
I seem to remember that the Simcom A6760E Breakout uses 3.3V logic
if you are connecting it to a microcontroller (UNO, Mega, etc) which uses 5V logic you require level shifters
Yes you are correct. I was planning on using a resistive divider between the Uno transmit, 10k between the Uno transmit and A7670 receive and 18k Uno Transmit to ground, to give 3.25V at the A7670 receive. I assumed that Uno receive wouldn't be a problem and that 3.3 V from the A7670 would be seen as a high by the Uno. However when I checked with SoftwareSerial loaded both the Transmit and Receive are at 5V under static conditions. As a divider wouldn't work in the other direction I changed the Uno for a Pro Mini 168 3.3V 8MHz and have sent my first SMS.