Mercury - NMEA 2000 T-Connector Network Expansion Tee 8M0204742. Overview. The Mercury 8M0204742 NMEA 2000 Tee gives you a simple, reliable way to add a new device to your N2K backbone. Whether you're installing a sensor, a display, or an engine gateway, this standard Tee provides the proper branch connection without clutter or guesswork. It's built to NMEA 2000 specifications and drops directly into any 5-pin network.. Key Features. Standard N2K Tee - Creates a clean branch point for adding NME