Does GSMVLP5 cellular communicator require a sim card?

While the Honeywell GSMVLP5 does require a sim card, the only sim card that is compatible is the card that comes pre-installed in the cellular alarm communicator. You cannot change the sim card to another network, or use your own sim card with the GSMVLP5. The GSMVLP5 must be installed in a L5000 LYNX Touch control panel, and must be activated with an AlarmNet dealer, using the MAC address, which is permanently tied to the sim card which comes with the device.