Meets internationally recognized requirements for RTCM- SC-101 Digital Selective Calling (DSC) that allows you to send a distress signal at the touch of a button, or exchange position information with other boats or stations (GPS receiver connection required). A convenient scan feature lets you search for conversations in progress. A noise canceling microphone with controls blocks background noise while the controls allow instant access to channels 16 amp; 9 and changing of channels and setting features. « less