CTX-3301 Fiber Optic Decoder for Mercedes W211 CLS SLK CL

The CTX-3301 Optic Fiber Decoder allows you to connect an aftermarket Android head unit to the original Bose or Harman Kardon sound system in your Mercedes from model years 2003 to 2008 in a neat and hassle-free way. Thanks to this decoder, which uses the original fiber optic connection, you do not need to run cables through the car to the trunk.

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

This optic fiber decoder is suitable for:

Mercedes CLS-Class (W219) – 2005 to 2008
Mercedes E-Class (W211) – 2003 to 2008
Mercedes S-Class (W220) – 2004 to 2006
Mercedes SL-Class (W230) – 2005 to 2008
Mercedes SLK-Class (W171) – 2004 to 2008
Mercedes CL-Class (W215) – 2004 to 2006
Mercedes B-Class (W245) – 2005 to 2008

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

How does the head unit Fiber Optic Decoder work?

The CTX-3301 converts the digital audio signal running from the amplifier to the speakers via fiber optics into a signal usable by an aftermarket head unit. This keeps the original speakers and amplifier fully active, while replacing the audio source with your new head unit.

This allows you to seamlessly switch to Android, CarPlay, or other modern systems without any modifications to the original wiring.

Connection & Installation

You can usually recognize the fiber optic connection by the orange cable behind the original factory head unit. The CTX-3301 is placed behind the aftermarket head unit and connected directly to it and the orange fiber cable. No cables need to be run to the amplifier in the trunk.

The installation is technically simple but requires basic knowledge of vehicle systems. The decoder comes with an installation manual to ensure you can perform the mounting correctly.

This product is exclusively required in combination with Bose or Harman Kardon. Do you not have an original premium audio system? Then the CTX-3301 is not necessary.

Frequently Asked Questions (FAQ)

Do all original speakers work with the CTX-3301?
Yes, all original speakers remain fully operational via the fiber optic channel.

Can I control each speaker individually?
No. Control occurs via 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 head unit via the fiber optic link.

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

Will my original CD changer still work after replacing the head unit?
No. If you have an original factory-installed Mercedes CD changer, it will no longer function after replacing the original head unit.

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-3301 is suitable for all common aftermarket Android head units with an RCA audio output.