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N2K Bridge

The Bristol N2K Bridge is a small box that plugs into your boat's NMEA 2000 backbone and puts the instrument data on Wi-Fi so Bristol Maps can read it. This page covers setting one up and looking after it.

What the bridge does

In the app's own words, the bridge "connects your boat's NMEA 2000 instruments -- GPS, depth, engine, wind, AIS -- to Bristol Maps wirelessly."

It carries two links:

  • Wi-Fi -- the full instrument feed. This is the normal way the app reads data.
  • Bluetooth -- used for setup and management, and as a slower backup that still shows navigation and engine data.

Every bridge ships with a QR sticker on the unit carrying its name and password. The name looks like BristolN2K-3F2A and the password like bristol-1A2B3C.

Before you start

The setup screen asks you to check three things:

  • The bridge is powered (its LED is on)
  • You're within a few feet of it
  • You can see the QR sticker on the unit

Setting one up

Go to Settings > NMEA & Instruments and tap + Add Bristol N2K Bridge.

If the app spots a bridge over Bluetooth when you open that settings page, a green card appears at the top saying Bristol N2K Bridge found nearby with a Set up button -- that starts the same wizard.

The wizard runs five steps.

1. Start setup

An intro screen with the checklist above. Tap Start setup.

2. Scan the QR sticker

Tap Scan QR sticker and point the camera at the sticker on the bridge. Camera permission is required.

If the sticker is damaged or unreadable, tap No sticker? Enter manually and type the bridge name and password from the label on the unit.

3. Connecting

The app finds the bridge over Bluetooth and checks the sticker password. Nothing to do here -- if it fails you get a Retry button and a Re-scan QR sticker button.

4. Choose connection

This is the important choice. You get two options:

Option What happens
Connect directly (recommended) The bridge runs its own Wi-Fi hotspot and your phone joins it. Simplest setup, but your phone is off the internet while it's on the bridge network.
Connect bridge to boat WiFi… The bridge joins your boat's Wi-Fi router instead. Your phone stays on the boat network -- no network switching, and you keep whatever internet the boat has.

For the boat-Wi-Fi option you enter Boat WiFi name (SSID) and Boat WiFi password, then tap Connect bridge to this network. The app waits while the bridge tries to join. If it can't -- usually a wrong password or weak signal -- the bridge returns to hotspot mode and you can try different details or fall back to the hotspot.

If the bridge is already on a boat network when you set it up, the app tells you which one and offers Use boat WiFi (name) as the first choice.

iOS: join the bridge Wi-Fi yourself

Automatic Wi-Fi joining is currently disabled on iOS. On an iPhone or iPad the hotspot path will tell you it can't join for you and offer I'll join the WiFi myself -- it shows you the network name and password, and you switch to the iOS Settings app, join that network, and come back. Android does the join automatically.

The other two fallbacks on that screen are Try again and Skip WiFi -- use Bluetooth only for now. You can set up Wi-Fi later from the bridge page.

No internet on this network

When you join a bridge hotspot your phone may warn you the network has no internet. Choose to stay connected / use without internet.

5. Checking live data

The app listens to the NMEA 2000 bus for a few seconds and counts instrument messages received. As data arrives you'll see ticks for what it recognised: Position ✓, Depth ✓, Engine ✓, Wind ✓.

A line at the bottom tells you which link is carrying the data -- bridge hotspot, boat network, or Bluetooth only.

If the counter stays at zero, the app says the bridge is connected but the NMEA 2000 bus is silent, and suggests checking that the bus has power and the bridge's backbone connection. You can still tap Finish setup.

Managing a bridge

Once set up, the bridge appears in the connection list on Settings > NMEA & Instruments with a Manage button. There is also an N2K Bridge group on the main Settings screen ("Bridge status, WiFi mode, reboot and maintenance").

The management page refreshes over Bluetooth every few seconds and shows four cards.

Status

Line What it tells you
Firmware Firmware version, plus how many frames the bridge has relayed and dropped
WiFi Hotspot or boat network, the SSID, the bridge's IP, and signal strength in dBm on a boat network
App link WiFi TCP with host and port, Bluetooth fallback, or not connected
Last seen "just now" if the bridge has been heard from in the last minute and a half, otherwise a timestamp

If the bridge can't be reached over Bluetooth you'll see "Showing last known values -- bridge not reachable over Bluetooth" and the numbers on screen are stale.

WiFi

One button that flips the bridge between modes -- Connect bridge to boat WiFi… when it's in hotspot mode, Switch to hotspot mode when it's on a boat network. Both ask you to confirm first.

Warning

Switching modes drops the bridge's connections briefly while it reconfigures.

Options

These come from the bridge firmware itself, so what you see depends on the firmware version. Options the app knows how to label include:

Option Description
NMEA 2000 RAW output Raw CAN frame output
NMEA 0183 output NMEA 0183 sentence output
TCP port The port the bridge serves data on
Bluetooth (next boot) Bluetooth on or off, applied at the next restart
Bluetooth name The bridge's Bluetooth name
Location source Where position output comes from

Location source is a picker with four choices: Auto -- prefer boat NMEA GPS, fall back to built-in, Boat NMEA GPS only, Built-in GPS only, and Both sources. The built-in options only mean something on bridge hardware that has its own GPS chip.

If the firmware doesn't report anything adjustable, the card says so.

Maintenance

Button What it does
Re-scan QR sticker Re-reads the sticker to update the stored password. It refuses a sticker belonging to a different bridge.
Reboot bridge The bridge drops offline for a few seconds and reconnects automatically.
Factory reset Resets the bridge to factory defaults. Asks twice.
Remove bridge from app Forgets the bridge on this device. The bridge itself keeps running and you can set it up again with its QR sticker.
Update firmware Shown but not yet available -- the button reads "Update firmware (coming soon)".

Factory reset erases the Wi-Fi setup

A factory reset wipes the bridge's Wi-Fi settings. It goes back to hotspot mode and the boat-Wi-Fi configuration is lost. You'll have to set the boat network up again.

Checking bus traffic

Two places tell you whether data is actually moving:

  • The live data step at the end of the setup wizard, which counts messages and names the categories it recognised.
  • The Firmware line on the management page, which shows frames relayed and, when it isn't zero, frames dropped.

For sentence-level detail, each connection in the list has a Debug button.

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