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4 votes
Accepted

Can't reduce SIM808 Power Consumption

Ok I finally could get the sleeping current advertised on the datasheet. First, I removed the buck converter and supplied 4V directly to the module so I get better efficiency and removed the supply ...
Andres's user avatar
  • 1,864
4 votes
Accepted

SIMCOM vs UBLOX

Your antenna supplier is probably also an U-blox reseller ;) Seriously - pretty much all cellular modules: Telit, U-blox, Gemalto [former Cinterion], Simcom, Quectel are basically the same (I've ...
filo's user avatar
  • 9,036
4 votes
Accepted

SIM808 registration denied for new SIMs

I got some help from an Aeris engineer with this one. It turns out that when a SIM first registers with the network, it requires better signal quality than subsequent registrations. When the SIM has ...
skot9000's user avatar
  • 113
3 votes

stm32f107 uart frame and noise error

So after watching my terminal for hours I realized something interesting!sometimes When ping request is sent to gsm module without any delay I get frame error and noise error. In reference manual I ...
Alireza 's user avatar
2 votes
Accepted

SIM808 always returns the same temperature

Simcom has discontinued the Temperature readout for cost down reasons. The diodes in the module which are required for temperature readout are no longer assembled. The feature was not useful anyway, ...
doc martin's user avatar
2 votes
Accepted

ESD clamping voltage in SIMCard interface too high

ESD diodes will dramatically reduce the effect of ESD pulses. You are right that the clamping voltage is still pretty high, but that is under specific test conditions that may not apply to your design....
user57037's user avatar
  • 29.4k
1 vote
Accepted

SIM868 powers down after few seconds

It is stated in the datasheet that the module will shut down in a few seconds if the supply voltage drops below 3V. The use of two diodes in series for dropping ...
vtolentino's user avatar
  • 3,589
1 vote

Sending/receiving a continuous stream of data using SIM7600

In my opinion it should go with the use of the microphone input and speaker output (not shure if there is one) on Maduino Zero 4G LTE board. You can initiate a call/activate sound reception/sound ...
Alex's user avatar
  • 11
1 vote

SIM7080 UART Noise interfacing with PIC18F4550

You can't really do this with dev boards. If you design a PCB with a cellular modem you need 33pF and 10pF on pretty much every trace. They filter out transmissions on 'about' 900MHz and 'about' ...
Michael Beaver's user avatar
1 vote

Assisted GPS (AGPS) on SIM7600 module does not work

I was using mode 1 and was getting GPS position that was off by about 30 miles. Got the solution directly from Waveshare: the decimal minutes need to be divided by 6. Once I know about that ...
terrydba's user avatar
1 vote

Are there regional constraints with the SIMCom modules? (Eg. SIM7605CE/SIM7600CE)

In 2018 Network Operators changed some specifications in SIM cards protocol. Happened that some SIM cards quit to work. To fix the problem you might have to update the firmware if your module. I and ...
Enrico Migliore's user avatar
1 vote

SIM7600A gives an error when executing commands, but works after executing it again

RS232 might be a bit unreliable if used with long cables or crummy cables, but the fact is that across the "distance" of a couple of centimeter from the Pi to the "hat" there ...
JRE's user avatar
  • 72k
1 vote

stm32f107 uart frame and noise error

it is usual symptom of the wrong baud settings. It can by the STM32 or the GSM device. The easiest way is to connect the oscilloscope and see the UART waveforms. Measure the timings and you will ...
0___________'s user avatar
  • 2,584
1 vote

STM32F4 and SIM800L logic level

I had the same problem. I solved it by setting the pulldown in the UART's pins' configuration.
John Wick's user avatar
  • 220
1 vote

Mcu keeps reseting because of noise

The output capacitance of the AMS1117 is too less, causing the 3V3 to be unstable. The datasheet recommends 22μF: The circuit design used in the AMS1117 series requires the use of an output ...
Huisman's user avatar
  • 10.7k
1 vote

SIM808 always returns the same temperature

It seems the version of the SIM800 Series User Manual that I posted above from Adafruit (v1.09) is out of date. The newer version v1.10 from simcomm2m.com mysteriously has the ...
skot9000's user avatar
  • 113

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