Cheap GSM module (SIM800) not connecting to the network

luhcforgh: Only the little curly wire thing (bottom left) was included - is this an antenna? If yes, where/how do I connect it, as just seems to be a piece of wire? Otherwise, will I have to buy an antenna like the one shown on the right of the image, or does it work without it? Are there any antenna specifications to consider?

Both are antennas, without one SIM800 cannot connect to network. The curly wire should be soldered to the top left hole (mine is labeled NET on the bottom). If you have the other antenna, just plug in on the u-fl connector (top left round connector).

luhcforgh: I have not yet been able to connect to the network, so perhaps this is the issue. I will also try lowering the TX/RX voltage from 5V, even if it seems as if I can communicate well with the module. I will also raise the maximum current to 3A, even if I don't think I ever got close to the limit. I'll try to remember to update this post if I reach any conclusions!

RX/TX are not 5V tolerant, do not connect more than 2,8V. Read previous posts to see how to create a level shifter.

SIM800L V2.0 5V

/* this library is writing by  Cristian Steib.
 *  Designed to work with the GSM Sim800l,maybe work with SIM900L
 *     This library use SoftwareSerial, you can define de RX and TX pin
 *     in the header "Sim800l.h" ,by default the pin is RX=10 TX=11..
 *     be sure that gnd is attached to arduino too. 
 *     You can also change the other preferred RESET_PIN
 *     Esta libreria usa SoftwareSerial, se pueden cambiar los pines de RX y TX
 *     en el archivo header, "Sim800l.h", por defecto los pines vienen configurado en
 *     RX=10 TX=11.  
 *     Tambien se puede cambiar el RESET_PIN por otro que prefiera
 *    PINOUT: 
 *        _____________________________
 *       |  ARDUINO UNO >>>   SIM800L  |
 *        -----------------------------
 *            GND      >>>   GND
 *        RX  10       >>>   TX    
 *        TX  11       >>>   RX
 *       RESET 2       >>>   RST 
 *   POWER SOURCE 4.2V >>> VCC
 *    Created on: April 20, 2016
 *        Author: Cristian Steib

#include <Sim800l.h>
#include <SoftwareSerial.h> //is necesary for the library!! 
Sim800l Sim800l;  //to declare the library
char* text;
char* number;
bool error; //to catch the response of sendSms

void setup(){
 Sim800l.begin(); // initializate the library. 
 text="Testing Sms";  //text for the message. 
 number="2926451386"; //change to a valid number.
 // OR 
 //Sim800l.sendSms("+540111111111","the text go here")


void loop(){
 //do nothing

TX 10 or 11
RX 11 or 10

I could not connect. Failure to complete :frowning:

Do you see module led blinking? How do you power that module? Print "error" variable to see what is happening.

Can sim800L chip work in EDGE network?

mortenx: Can sim800L chip work in EDGE network?

It works only in EDGE network

EDGE is 2.5G and GPRS is 2G.

I am in Estonia and we have 3 networks Telia,Elisa and Tele2 ... and SIM800 chip sees only Tele2 network... why so ?

Dont try ot on my own, but the documentation says, you can switch the EDGE Mode On or Off. on page 200

this CEGPRS command gives error.. is there some command that comes first ?


Same problem, module is seeing network but dont connect...

Finding Networks. Please wait..


+COPS: ,(0-4),(0-2)

OK Available Networks: Finding Networks. Please wait..


+COPS: (1,"TELE2","TELE2","24803"),,(0-4),(0-2)

OK Available Networks: Network Name->TELE2 Network ID->24803 Network Status->Available




Call Ready

SMS Ready

You can visit the site for more information, click here

I have purchased SIM900 and still waiting for SIM800C and SIM800L. Firstly I attached my SIM900 directly to the UNO and it didn’t connect to the network. Afterwards I tried it over a breadboard supply and the result was the same. Still I have several 2G networks available. So after a triple flash on the SIM900 module a NetLight (D6 led diode) goes off. Now I’m waiting for an AC/DC power supply with 5V and 2A, some ESR capacitors, diodes,… for more tries. In my opinion some of these problems comes from 2G network unavailability while some are power supply related. According to the datasheet from the manufacturer all these SIMs need 4 Volts and in peak 2 AMPS, either through a boost or a DC-DC converter. I plan to make a small circuit and to position it the closest possible to the VBAT (34, 35 pins) and GND (36, 37) as shown in two attached JPEGs. If you are making your own PCB board the manufacturer also recommends lines at least 1 millimeter thick. Hopefully this could solve some of our issues.

2g sim card is not available here in India so i like to have some advice what to do if gsm module800A not registering on network

Check if the IMEI number written on the module matches the number that you receive on the AT+cgsn command.

I have the same problem described here (cannot register to network) and these numbers do not match and I suspect that the issue is that I might have a cloned module.

AT command is not working..!!

Jayesh_Adwani: 2g sim card is not available here in India so i like to have some advice what to do if gsm module800A not registering on network

SIM800 is a 2G modem, if 2G is not available in your country, you cannot use it.

Any idea which module to use..?

Well, check UMTS modules like sim5320 or the new narrowband (if available in your country) like sim7000

Thanks anyway..!!

Try to see this video

I have the same problem, please help me. I use the GSM library, GSMSim_SIM example to link ESP8266 and Sim800c. I received

this messages in Serial Port.