“Bridge Connection reset” allows you to disconnect from the bridge (Envisalink). It also represents the connection status to the Envisalink; ON being ‘connected’ and OFF being ‘disconnected’.
“Send a DSC Alarm Command” is a channel that allows for the sending of raw commands to the Envisalink. It was created as a replacement for the DSC action add-on that was part of OH1. Here is a link to the discussion on this: DSC Alarm Action in OH2.