I have a M590e GSM module (assembled from a kit)

it is this kit in this link


I have sucessfully interfaced he module a PC and it does recognise AT commands sent through the serial port. When the module starts up (with sim inserted) it does NOT say PBREADY. After waiting a few minutes after startup.

I type in the command (with the sim inserted of course)


I get the response


which I think means it is searching for a network. When I take the sim card out of its holder and measure the voltage pins that supply power to the sim card (the VCC,GND pins in the sim card holder) I get a reading of 0.01v with a multimeter-is this normal?-should it be at least 1.8v here?-does the voltage increase in specific circumstances when the sim is inserted? Im not sure, but is my module faulty? I cant figure out what the fault is. I have been unable to connect any sim to a UK network so far-and I have tried three different sim card (all known to be working from testing in a phone).

  • \$\begingroup\$ Does your SIM have a pin code check enabled? Are you sure you're measuring the voltage right (between C1 and C5, not touching anything else with the probes)? \$\endgroup\$ – Dmitry Grigoryev Aug 23 '17 at 14:26

This module is pulling a lot of power. I had to use a 5v/1500mA powersupply, but also I had to add a big capacitor also! I soldered a 2200µF at the input of the GSM m590 module. And don't forget to put the "BOOT" pin on ground.


Looking at https://cdn.instructables.com/ORIG/FX6/UAHQ/IZ6CYGIU/FX6UAHQIZ6CYGIU.pdf I think the 2 is "The registration is refused". Not sure if it means you have an usable SIM. 3 is "not registered, the terminal is searching base stations"


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.