How to update Raymarine AIS4000 and AIS5000 – Tips for correct termination of RX ports

Learn why your AIS unit may request an update after installation and how to terminate unused RX ports with 120-ohm resistors for optimal performance.

Keeping your AIS4000 or AIS5000 updated is crucial to ensure the best possible performance and reliability on board. In this guide, we explain why your AIS unit may sometimes request a software update even after an update has been performed, and how to correctly terminate unused RX ports to avoid operational problems.

Why does the AIS unit request an update?

After an update, the unit may still display messages about the need for an update if certain hardware settings are incorrect. A common problem is that unused RX ports are not terminated, which can affect the system's initialization.

Terminate unused RX ports – how to do it

A pack of six 120-ohm resistors is included with the AIS4000. These are used to terminate unused ports and ensure correct function.

Step-by-step:

1. Connect the 14-way and 18-way cables according to the manual.
2. Terminate all unused ports with a 120-ohm resistor across the RX A and RX B signals.
3. See the image below for correct placement:

Use the included resistors and a terminal block (not included) to terminate the ports as shown in the diagram above. Alternatively, you can use the optional junction box accessory for easier installation.

What happens if the RX ports are not terminated?

If the unused RX cables are not correctly terminated with 120-ohm resistors, the AIS4000/AIS5000 may fail to initialize and display an error message. See example below:

Solution: Terminate the cables according to the instructions above to restore normal operation.

Download manuals and documentation

For detailed instructions and wiring diagrams, download the relevant manuals for AIS4000 and AIS5000 from Raymarine's official website.