sim900 Polish operator play

Hi,
We have used sim900 (fw revision 1137B10SIM900M64_ST) modem in three different countries with three different operators. (O2, Orange, Plus)
We have mainly used data transfer using GPRS.
Now we need to use sim900 module in Poland with polish operator Play. There are two problems which I have encountered so far.
1) Very often it is not possible to register into GSM network. AT+CREG?\r returns 0, 2 or 3.

2) Sometimes when registration into GSM is successful then AT+CGATT=1\r returns ERROR.

Mobile internet is working OK with another polish operator Play.
I found similar thread: https://www.edaboard.com/threads/296777/ but there is no resolution. In that thread they refer to command AT+COPS.
I don't use this command in the program and so far it worked fine. What is the default value of parameter 'mode' ? I guess that it is 0 - Automatic mode.

Have you connected antenna with your sim900 and AT+COPS returns with the operator name

like for example it's mentioned in the datasheet of sim900 "AT+COPS?" , then the response comes from it is is the operator name like I am using AIRTEL in INDIA so it returns

as "airtel"

Yes I have antenna connected to sim900 modul. It works fine with different operator.
I also understand that AT+COPS? returns operator name. However AT+COPS? returns name of operator after successful registration into GSM network and my
problem is AT+CREG? returns that registration into network was denied.
I dont uderstand if I have to process and choose operator based on information from AT+COPS? if I have set automatic mode.

Hi Sk

do one thing

in the terminal only just for checking you type

AT+CREG?
then
whatever be the result code is there

You now type


then check AT+CREG? again

and then after go for AT+COPS?

Hi
I don't have interractive application so I don't have terminal + I'm not currently in Poland.
When I will be there I will modify our app and try your suggestion. + What reaction do you expect from this order of commands?
Meanwhile I have found that Play is from large part virtual operator. So what should be output of AT+COPS? Play or operator from which Play is borrowing hardware?
Is there any specific AT command that must be used when using virtual operators? I haven't found any such command in documentation.
What will I in this case gain when I will allow unsolicited codes for CREG=1? Those codes will be only what returns CREG? in <stat> field.

AT+CREG = 1;
This will enable your network Registration only ,
and regarding the Virtual Operator I am not sure whether it'll give the real operator name but, still I think in mobile There is another operator name always if the SIM Card operator Networking is not available in that particular city

So from mobile devices it's showing another operator name only So I GUESS that it will give the result in virtual operator name only

Commands manual says that AT+CREG = 1 Enables network registration unsolicited result code. It does't say anything that this command has to be used in order to enable registration into network.

No, I usually don't need AT+CREG=1 to register if memory serves correct.