The following functions are used to get the status of the cellular modem:
•gsmBER
Returns the Bit Error Rate
•gsmConnected
Checks connection to the GSM network.
•gsmGetIMEI
Gets the IMEI number of the GSM module.
•gsmGetStatus
Returns the status for the GSM network connection.
•gsmSignalLevel
Returns the signal level for the GSM connection.
