Cheap GSM module (SIM800) not connecting to the network

Hello.

Try changing the position of your sim card.

This is a very common error.

Best regards.

sim800 insert like this.png

That was definitely not it, since the SIM card was getting recognized by the module.

I also have this problem with a different breakout board. The weird thing is, when I put in a different sim, the module suddenly does work.

Well I've received exactly the same module as the youtube video, but looking at the data sheet, it specifically says that the power input should be around 4V-2A, just bought a adjustable DC-DC converter with an LM2596:

http://www.aliexpress.com/item/1pcs-LM2596-LM2596S-DC-DC-3-40V-adjustable-step-down-power-Supply-module-NEW/1116954291.html

The data sheet also mentions that the data lines should have a max voltage of 2.8V. And a suggested circuit for adapting from 3.3V to 2.8V appears on page 31 of the hardware design guide:

http://simcomm2m.com/UploadFile/TechnicalFile/SIM800L_Hardware_Design_V1.00.pdf

So I think that connecting this directly to an arduino possibly isn't the right choice... The power supply doesn't provide enough current and data lines need some circuitry in order to work.

I have the same problem in registration the sim to the network the AT command are working properly until I use AT+cmgs=......
ctrl+z ...send amsg then it return error

I use orange ..jordan network

I have been working on a home alarm project for a while. I think I can answer some of the questions here on this thread...

Through my work, I have been using this AT-Command manual for Sim800 - https://www.adafruit.com/datasheets/sim800_series_at_command_manual_v1.01.pdf

nikola1010:
I have the same problem but also every once and then SIM800L outputs on it's own:

+CFUN: 1

+CPIN: READY

Call Ready

SMS Ready

Call Ready

SMS Ready




What could be the issue?

For me, this happens when I send an AT-command before the module gets contact with the network. The Call/SMS Ready are then sent as the module connects to the network.

When I wait for the module to connect before I send my first AT-command, I do not get such messages.


karamelo:
Well I've received exactly the same module as the youtube video, but looking at the data sheet, it specifically says that the power input should be around 4V-2A, just bought a adjustable DC-DC converter with an LM2596:

http://www.aliexpress.com/item/1pcs-LM2596-LM2596S-DC-DC-3-40V-adjustable-step-down-power-Supply-module-NEW/1116954291.html

The data sheet also mentions that the data lines should have a max voltage of 2.8V. And a suggested circuit for adapting from 3.3V to 2.8V appears on page 31 of the hardware design guide:

http://simcomm2m.com/UploadFile/TechnicalFile/SIM800L_Hardware_Design_V1.00.pdf

So I think that connecting this directly to an arduino possibly isn't the right choice... The power supply doesn't provide enough current and data lines need some circuitry in order to work.

I fixed the RX/TX issue by putting a zener to lower the arduino TX signal. Like here: 404 Error

The other line is good to go; the arduino senses 2.8V signals.

I also got my 4V power source by lowering the arduino 5V with a zener.


theanat2010:
I have the same problem in registration the sim to the network the AT command are working properly until I use AT+cmgs=......
ctrl+z ...send amsg then it return error

I use orange ..jordan network

I do not really understand, but if you communicate directly with the module (through terminal) there is no way (if there is, I have missed it) to send <ctrl+z> as this is char no.26 (GSM charset)
My workaround was this: (a slight modification of the SoftwareSerial example)

void loop() // run over and over
{
  if (mySerial.available())
    Serial.write(mySerial.read());
  if (Serial.available()){
    char c = (char)Serial.read();
    if(c == '#')
        mySerial.write((char)26);
    else
        mySerial.write(c);
  }
}

Hope this will help you!

//Egad

Don't forget ; character if you try to call:
ATD+7916XXXXXXX;

Hi All

I have exactly the same problem with a similar module:

http://www.ebay.co.uk/itm/New-SIM800L-GPRS-GSM-Module-SIM-Board-Quadband-L-shape-Antenna-for-MCU-Arduino-/161698611153?hash=item25a5fcffd1

I have a 2Amp 5v regulated supply powering the unit, so no power problems here.

Here is the response I get when trying to register:

AT+COPS=?
+COPS: (2,"vodafone","voda UK","23415"),(3,"T-Mobile","TMO UK","23430"),(3,"O2","O2 -UK","23410"),,(0-4),(0-2)

OK

AT+COPS?
+COPS: 1

OK

And when I try to register to the Vodafone network manually:

AT+COPS=1,0,"vodafone"
ERROR

So it seems very much as if the module is unable to connect to UK networks.

ANY INPUT WOULD BE GREATLY APPRECIATED.

Kind regards
Simon

Hi,

I have been working some years with the SIM900 which is similar to SIM800 (got one of
these too but haven't tested) and the problem with not registering to the network depends on the network operator.

The SIM modems (800 /900) does NOT support 3G/4G only 2G. So if the network operator request to use the 3G network for startup (this is determid by the operator when programming the SIM card) it will not be possible to register.

I have tested with many different SIM cards around the world and this seems to be the logical explanation (I have also contacted SIMCorp to see if any commands could be use to change the startup and force the modem to regsiter). If you select a network operator the use 2G for start up (I have seen
af patterne that pre-paid SIM card often work - guess they are setup to be used for any mobile device).

Hi,

Does anybody use this kind of modules with a power supply of 5V and a simple DIODE ???? How long ?

Thanks a lot.

Don't use a diode unless your power supply is very stable.
i've used that module with a external power supply regulated to 4.95V with a diode to down voltage to 4.25V. Then i replaced the power supply for a pack of batteries (5.08V), after that i got strange behavior, sometimes SIM800 didn´t send any messages. I figured that at 5.08V, the voltage on the SIM800 was 4.35V that leeds to OVERVOLTAGE warnings. Better is to use a LDO or some external power very stable, around 4.2V

geologic:
Don't use a diode unless your power supply is very stable.
i've used that module with a external power supply regulated to 4.95V with a diode to down voltage to 4.25V. Then i replaced the power supply for a pack of batteries (5.08V), after that i got strange behavior, sometimes SIM800 didn´t send any messages. I figured that at 5.08V, the voltage on the SIM800 was 4.35V that leeds to OVERVOLTAGE warnings. Better is to use a LDO or some external power very stable, around 4.2V

Could be the real problem the fact that batteries can't supply the 2A peak that SIM800L could need sometimes ?

Regards,

Not the case. as soon i replaced the diode for a 4V LDO, everything went to normal.

Despites specs saying Sim800 can consume up to 2A current, in my tests i never measured more than 350mA. I'm using a regular multimeter and only use GPRS functionality, never tested with voice or SMS.

It's not only about the Vcc power, pins need also a voltage divider. The serial port characteristic of the spec says 2.8 V max:

see p. 31 http://www.seeedstudio.com/wiki/images/4/46/SIM800L_Hardware_Design_V1.00.pdf

Clemens:
It's not only about the Vcc power, pins need also a voltage divider. The serial port characteristic of the spec says 2.8 V max:

see p. 31 http://www.seeedstudio.com/wiki/images/4/46/SIM800L_Hardware_Design_V1.00.pdf

Yes, it could be. But sometimes these modules came with a voltage "translator" and you can use a 5V signals, but you have to be really carerful with power voltage, not to burn it.

May be a diode is faster o slower than others? (i don't know about this kind of problem)

Regards,

juan3211:
Yes, it could be. But sometimes these modules came with a voltage "translator" and you can use a 5V signals, but you have to be really carerful with power voltage, not to burn it.

Yes, mine is 5v tolerant, no need for level shifting

Maybe a diode is faster o slower than others? (i don't know about this kind of problem)

Regards,

for supplying power i think it's irrelevant, just use one rated for 2A or higher

Today i received the same module with same problem. Red LED blink fast and typing AT+COPS? the answer is AT+COPS:0.
I powered the module with 3 D Cell with a DIODE, the voltage supply is about 3.9V=(4.5-0.6)V
The bheaviour are strange! Sometimes the module accept commands sometimes not! Can someone an give me tricks?
I think that i threw my money away, not is the first time! In the past i tested more GSM module.
With TELIT i never had problems, but when i started to test cheapest SIMCOM (assembled by various/unknow Chinese company) it was a Hell! 900 ok, 900A don't run in Europe, 800L with direct connection (like reported by vendors) to 5Vcc of Arduino board (burn various LM1111).

Are you sure you are powering at 3,9V? Measure it with a voltimeter when SIM800 is ON, i guess your batteries cannot mantain a steady 4,5V

I had one working for a month and suddenly it stops working. I was powering it with 4V but RX/TX lines were connected directly to 5V arduino ports.
I replaced by a spare one but this time add a level shiftter between arduino and RX to lower the signal to 2,8V. It is running now for 2 weeks without a fault.

For my experience, i advise:

  1. Power SIM800 with a 4V LDO. Use a diode only if your input is very stable
  2. Keep RX/TX lines below 2,8V

geologic:
Are you sure you are powering at 3,9V? Measure it with a voltimeter when SIM800 is ON, i guess your batteries cannot mantain a steady 4,5V

I had one working for a month and suddenly it stops working. I was powering it with 4V but RX/TX lines were connected directly to 5V arduino ports.
I replaced by a spare one but this time add a level shiftter between arduino and RX to lower the signal to 2,8V. It is running now for 2 weeks without a fault.

For my experience, i advise:

  1. Power SIM800 with a 4V LDO. Use a diode only if your input is very stable
  2. Keep RX/TX lines below 2,8V

Can you please attach circuit diagram. I also experience such problems, Used one SIM800L for a month, then is stopped registering in the network, when I pull TX line from SIM800L, restart the module it registers in the network, then put TX back and it works, then if I reset the Arduino, it resets the SIM800L and can't register in the network again. Looks like problem is with module's serial ports, will test another one with voltage dividers...

Strange thing is no matter it's registered or no, it responds and communicates with Arduino OK, displays found networks, but when I send command to connect to the carrier AT+COPS=0,2,"40001" for example it responds ERROR....why?

I had same problem with SIM800 module and the problem was the supply current.

I recommend:

  1. Test SIM card in your mobile in order to verify if it is working properly (maybe the SIM card is damaged)
  2. Try to supply the SIM800 with an stable source 4,1V@3amp. Its important to know if your problem is a supply current problem to discard any other issues.

In my case I used a DC-DC converter from 12V@2.5amp to 4,1@2.5amp and now it works properly. If the module is connected to a source without enought current, the SIM800 module will reponse to AT commands but all of these commands relationated with the SIM will not work.