The integration of VHF hinges on two features: DSC (Digital Selective Calling) and AIS (Automatic Identification System). DSC enables your VHF radio to initiate a call that also communicates your GPS position. In an emergency, this feature tells the Coast Guard, as well as other boats, where you are. In non-emergency situations, DSC allows for discreet communication — say, for sharing fishing information you don’t want to broadcast to everyone with a radio or for keeping track of your friends on the plotter. AIS is an identification system that transmits vessel data, such as size, type, speed and bearing, to anyone with an AIS receiver, and it also provides the MMSI of a vessel.