GSM system according to the theory , the phone receives more than three slots ahead of launch (about 18MS) mobile phone system rather than looking to find the phone system , the receiver decided to launch , say, the phone is the first to receive the transmitter , which is the principle of the mobile phone network If the phone is faulty reception , the base station does not receive the channel assignment information , the transmit path can not enter the standby state, the phone number , as long as the receive channel is good, the display will have a signal strength value , regardless of the presence or absence of signal emission . such as: Samsung series Ericsson series of mobile phones .

 

    Therefore, in the absence of network services, operators should first determine whether the problem , look at someone else's phone without a signal , and if so, remove the SIM card for a cell phone to try, if the signal , you can determine the problem lies in the phone , the tone menu , use the manual search methods to find the network , if the search to " China mobile" or " China Unicom " , the receiving part of the normal , while the transmitter circuit failure , if "No network Service " describes the receiving channel has failure at this time , if your antenna without exception , you can take the maintenance department to explain the situation and let him repair it.