I have set the baud rate of sim808 module to 57600 and with a USB2TTL module connect it to my PC. Everything works fine and the module recognize the AT-Command except that constantly send the following message to the terminal

+CFUN: 1
Call   Ready
sms    Ready

I wonder to know how can I stop sending these messages, Is it possible that the module reset itself?

PS: Power indicator light is on and GSM Net light indicator is blinking. PWRIN Voltage is 5V

  • \$\begingroup\$ What are you using as a power source, and what is regulating it down from 5v? It's actually quite challenge to devise a non-battery source that can stand up to the peak pulse power needs of GSM, especially in its older forms as many of the UART interface modules implement. \$\endgroup\$ – Chris Stratton Sep 12 '17 at 18:34
  • \$\begingroup\$ Thanks Chris for your reply I use laboratory power supply that is capable of 5A \$\endgroup\$ – Mohammad Yousefi Sep 12 '17 at 18:39
  • \$\begingroup\$ But what regulates it down to the ~4 volts the SIM808 actually requires? And what sort of wiring have you used? Depending on the regulator used and it's dropout (especially when sourcing what is likely out-of-spec current) your input voltage may actually be too low. \$\endgroup\$ – Chris Stratton Sep 12 '17 at 18:42
  • \$\begingroup\$ As in the Link says "Note: PWRIN range is from 5.0V to 10V, 5.0V is recommended," so I gave that pin Exactly 5V. the module has internal regulator \$\endgroup\$ – Mohammad Yousefi Sep 12 '17 at 19:11
  • \$\begingroup\$ But what is the internal regulator? You can't assume that the person who designed this knew what they were doing. \$\endgroup\$ – Chris Stratton Sep 12 '17 at 20:08

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