How to find Network that your phone locked to

Hi. I searched on the forum and could find the answer to this question. I have Nokia 6230b, bought it on eBay. It said that it is unlocked and it works fine with T-Mobile. Only during the peak time (weekdays afternoon) it locks up saying "Phone Restricted" or "Insert SIM Card". When I checked restrictions (#pw+1234567890+1) it said "Emergency Calls Only". Did anyone have the same issue? Or maybe someone know how to resolve it. I can't try to unlock it since I don't know what provider it is locked (if it is).

 

Post your IMEI# and I'll check it.

 

353372006550905

 

Locked to Cingular

#pw+028493042676400+1#

 

Thank you for the code. But when I inputted(according to your instructions) nothing happened, and I realized that actually when I input(#pw+1234567890+1#) nothing happens either. Before I pressed "call" button at the end that's why it gave me "Emergency Calls Only". So I guess my phone doesn't have any restrictions. It came in original nokia box, but I still can't understand why my phone locks up during the day, must be a provider problem.

 

using #pw+1234567890+1# is to check lock status on a DCT3 phone not on a DCT4 that's why nothing happens.

 

could you tell me the code for DCT4 phones to check the restrictions?

 

Insert a non accepted sim, press undo option, enter the code in the restriction box and press enter or OK.

 

Ok, I will try that during my next lock up.

 

tried code when phone became restricted, didn't work. Displayed "Code error"
anything else that I can try

 

@alexua

Hardware problem. UEM or UPP, or may be filter soldering...