Audi 80 with a car radio that has CAN bus connectivity.

Hello,

I also have an Audi 80 and I'd like to install a navigation system from an Audi A4 with an SD card slot into it.
However, my Audi 80 does not have a CAN bus system.

As far as I know, there are adapters that translate the signals. Are these readily available for purchase, or does one have to build them from scratch?

There are ready-made adapters that translate signals from the lights and ignition into CAN messages. Apparently, there's also one available for TT Friends that even activates the radio display in the FIS (Multi Function Instrument). The RNS-E needs to be coded for an A6 vehicle, and the GALA line must be connected to pin V for the navigation to function.

Do you know where I can buy ready-made adapters?
I don't have a FIS (facility interface system) in my Audi 80, so all this device needs to do is process the lighting and speed signals.

I don't have any experience with these adapters, but you can usually find them on **** .de. Alternatively, you could check out Kufatec.de. By the way, the speed signal doesn't need to be converted; for coding the RNS-E for an A6, the Gala signal is sufficient.