SIM card logging - What to check if SIM cards do not log into network?

Please check that

• Antenna is correctly connected
• PIN is deactivated or right PIN code is provided in Gateway configuration/System parameters
• Wavecom has right frequencies set in Gateway configuration/GSM Basic parameters/Multi-band selection. You can check frequencies used in your country on Wikipedia (This applies only for gateways with order numbers starting  505105.. You can find order number on label on the back side of gateway)
• Gateway configuration/GSM Outgoing groups/Roaming enabled for network code is set in case of SIM from foreign country or in case of SIM of virtual operator who uses infrastructure of the different operator. By default the gateway allows SIM to log only to home network. Code of SIM and code of network must be the same. This parameter allows usage of other network than the home network. The network is specified by 5-digit code. You can find these codes on Wikipedia. X is used as wild character. For example 23001 allows SIM to log to T-mobile Czech Republic and 230XX allows SIM to log to any network in Czech Republic. This parameter do not show which network should be used. The offer to accept SIM comes from the network and the gateway can allow logging or reject the offer.
• There is no time restriction set in Gateway configuration/GSM Outgoing groups. By default SIM is allowed for the whole week from 00:00 till 24:00.
• SIMs work in cell phone.
• Cell phone shows good signal level.