Actisense Micro 4-Way Instrument DropMicro 4 Way Instrument Drop The Actisense 4 way drop makes it easier to reach up to four devices with a single cable. Typically, when four devices need to be connected to an NMEA 2000 backbone, a T piece and individual cable is required for each one. This can either mean excessive cabling demands or moving the backbone closer to your devices. The 4 way drop makes it possible to shorten the length of each cable needed before reaching a T piece.