Cellular devices and a pairing server implementing a Pairing method are described. The first cellular device includes a first subscriber identity module (SIM) card, a controller and a transceiver. The first SIM card is configured to store a first international mobile subscriber identity (IMSI). The controller is configured to receive a pairing command. The transceiver is configured to transmit the first IMSI without a Mobile Subscriber Integrated Services Digital Network-Number (MSISDN) in response to the pairing command.