Overview

The Garmin 010-12390-11 is a 6-foot (1.8 m) OTG adapter cable that lets a GPSMAP 8400 or 8600 series chartplotter power an external device over USB. It gives you a secure, water-resistant connection at the chartplotter end so the USB power lead can live behind the helm without feeling like a loose electronics cord.

On board, it is commonly used to keep a phone topped up at the console or to run a small USB-powered accessory from the chartplotter. It can also supply power to streaming devices like Chromecast or Roku when paired with an HDMI coupler and HDMI cable (not included) for streaming video to the chartplotter.

Key features

• Made for GPSMAP 8400 and 8600 series chartplotters
• 6-foot (1.8 m) cable length for easier routing from the display to a mounting shelf, glovebox, or electronics locker
• Secure, water-resistant connection at the chartplotter end for typical helm spray and washdown environments
• Powers an external device via USB from the chartplotter, such as a phone or media player
• Can supply USB power for Chromecast or Roku when used with an HDMI coupler and HDMI cable (not included) to stream video to the chartplotter

Compatibility and fit

This adapter cable is intended for Garmin GPSMAP 8400 and 8600 series chartplotters. Confirm your display family before ordering, especially if your boat has multiple Garmin displays from different generations.

Installation and setup

Plan the run like any helm wiring: keep a drip loop where it makes sense, avoid tight bends, and support the cable so vibration does not work the connection loose over time. The 6-foot length is usually enough to reach from the back of a flush-mounted display to a protected storage spot where you can plug and unplug a USB device without pulling the display.

For streaming sticks, power the device from this cable and use the appropriate HDMI coupler and HDMI cable (not included) for the video connection. Keep the streaming device in a dry, ventilated spot behind the console so it stays accessible but out of direct spray.

Use cases on board

This is a practical add-on for boats where the helm becomes the charging station during long days of navigation or fishing. It also fits installations where you want video streaming at anchor without running an extra USB power lead from a separate outlet.

Maintenance and care

If the connection lives in a saltwater cockpit, a quick wipe-down after washdowns helps keep residue from building up around the plug area. Check the routing occasionally for chafe points and re-secure the cable if it has started to move with vibration.