CTX-3302 | Fiber optic decoder | Mercedes ML W164 | GL X164 | R-Class W251

The CTX-3302 Fiber Optic Decoder makes it possible to neatly and effortlessly connect an aftermarket Android head unit to the original Bose or Harman Kardon sound system in your Mercedes. Thanks to this decoder, which utilizes the original fiber optic connection, you do not need to run any cables through the car to the trunk.

This allows you to retain the original amplifier and speakers while still enjoying the latest infotainment features of an aftermarket head unit.

This fiber optic decoder is suitable for:

Mercedes ML-Class (W164) – 2005 to 2011
Mercedes GL-Class (X164) – 2005 to 2011
Mercedes R-Class (W251) – 2005 to 2011

✅ Only suitable for vehicles with Bose or Harman Kardon audio via fiber optics (MOST system)

How does the head unit Fiber Optic Decoder work?

The CTX-3302 converts the digital audio signal running from the amplifier to the speakers via fiber optics into a signal usable by an aftermarket head unit. As a result, the original speakers and amplifier remain fully active, but the audio source is replaced by your new head unit.

This allows you to upgrade to Android, CarPlay, or other modern systems without making any changes to the original wiring.

Connection & Installation

The fiber optic connection is usually identified by the orange cable behind the original factory radio. The CTX-3302 is placed behind the aftermarket head unit and connected directly to the radio and the orange fiber cable. There is no need to run any cables to the amplifier in the trunk.

The installation is technically simple but requires basic knowledge of automotive systems. The decoder comes with clear labels for the connection.

This product is only required in combination with Bose or Harman Kardon. If you do not have an original premium audio system, the CTX-3302 is not necessary.

Frequently Asked Questions (FAQ)

Do all original speakers work with the CTX-3302?
Yes, all original speakers remain fully functional via the fiber optic channel.

Can I control each speaker individually?
No. Control is routed through a single shared fiber optic channel. Individual speaker control per channel is not possible.

Is the original amplifier retained?
Yes, the original Bose or Harman Kardon amplifier remains fully active.

Do I need to run cables to the trunk?
No, that is not necessary. The connection is made entirely behind the radio via the fiber optic link.

Is the decoder suitable for every Mercedes?
No, only for the listed models with Bose or Harman Kardon and the MOST fiber optic system.

Can I connect any aftermarket head unit with this?
Yes, the CTX-3302 is suitable for all common aftermarket Android head units with an RCA audio output.

Will my original CD changer still work after replacing the radio?
No. If you have an original CD changer supplied by Mercedes from the factory, it will no longer function after replacing the original radio.

Can I continue to use the original radio antennas?
No, it is not possible to reconnect the original radio antennas to an aftermarket head unit. In that case, we recommend using free digital radio via CarPlay or Android Auto.

Can I connect any aftermarket head unit with this?
Yes, the CTX-3302 is suitable for all common aftermarket Android head units with an RCA audio output.

Important to know

This item is only necessary if your Mercedes is equipped with an original Bose or Harman Kardon audio system with fiber optics (MOST). Without this system, the decoder is not needed and a standard connection works simply via speaker wires.