The Victron GSM GX is a cellular(moible phone network) modem; providing a mobile internet for the system and connection to the VRM Portal.
Antennas and accessories
GSM: A small indoor GSM antenna is included. An outdoor GSM antenna is available as an option:
GSM900100100 - Outdoor 2G and 3G GSM Antenna for GX GSM
GPS: The unit has a built-in GPS receiver. An antenna is not included; to use the GPS received; purchase the GPS Antenna.
GSM900200100 - Active GPS Antenna for GX GSM