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Using EHS6T with Unitronics Unistream PLC (AT&T SIM) | Thales IoT Developer Community

August 16, 2018 - 4:24pm, 1017 views

A customer of mine was sold a Unitronics PLC with an EHS6T modem with the understanding that he would be able to send emails from the PLC.  I am a PLC expert, not a GPRS modem expert, but I have spent over 30 hours on trying to get this project to work, and I am stumped.  The PLC uses two instructions, one to initialize the modem, and the other to initialize the GPRS.  I only have a few variables that I can modify.  They are labled and filled in below:

Pin Code

GPRS APN     wap.cingular

GPRS User     wap@cingulargprs.com

GPRS Password   cingular1

The Init Modem command replies that it is successful, but the Init GPRS command fails every time.  There is no diagnostics on the PLC, so I have been using AT commands to try and figure out what is wrong.  I have also called AT&T, and they claim that the SIM card is provisioned correctly.

Here is my question, what AT commands can I use to find out where the problem lies?  Thanks in advance for any help you can provide.