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I have a 2000 Mercedes‑Benz R129 SL320 with the factory Audio 10 BE3100 (Becker) radio (shown in the link below). I’d like to add Bluetooth streaming (A2DP) and hands-free calling (HFP).
From what I understand, this radio uses a D2B fiber-optic CD changer interface, so a typical Bluetooth CD emulator that outputs analogue audio won’t connect directly.
I’m looking for advice on using a D2B fiber-optic decoder/interface in conjunction with a Bluetooth CD changer emulator to get music and calls working properly.
My main challenge however is locating these components, particularly a D2B fiber-optic decoder compatible with my car/radio. Most of the decoders I am finding online state they are compatible with SL R230 2001-2006, so I doubt they will work on the R129. Some say they are compatible with SLs but don't specify the model.
Has anyone successfully sourced or purchased these components for an R129 Audio 10 setup? Any guidance on where to find these devices would be greatly appreciated.
My 2000 SL500 has Becker audio 30.
I found a company that installs additional Bluetooth modules inside old Becker radios.
I also have fiber optic cable for CD changer (it wasn’t used for modification) and now every audio source is working properly like it was before Bluetooth modification.
The Bluetooth module is connected to old Phone button and this button turns on BT streaming and phone calls audio (I still need to pick up the phone on my iPhone screen after selecting BT audio on Becker unit).
If you are located in Europe I can send you phone number to this company. It’s in Poland. They charge about 300-400 PLN (70-100€). They can install BT module in any old backer unit.
alternatives: buy a modern continental head unit with Vintage look. I don’t remember the model number. Just search on Amazon or eBay. Blaupunkt also makes vintage look modern radio with BT. Blaupunkt Frankfurt radio or other models.
The two replacement units mentioned in prior repsones seem to be the go to ones.
If you prefer to keep the original head unit, Becker Audio will retrofit it to support bluetooth. Given I have a low mileage good condition vehicle I think originality is going to become important so that is what I plan on doing with mine.
I am big on originality, I did a load of research before going down the Blaupunkt road.. Basically my justification was as follows..
1. In every region in the world the R129 had a different headunit installed.. Here in Australia it was a Eurovox unit, with a CD stacker in the boot. This unit was exactly the same one used in a Holden or a SAAB, it simply had each cars logo printed on the tape flap.. It was perfectly fine, but certainly not a critical item that was unique to the R129.. (I'll post a picture)..
2. If you are converting an "original" unit to add BT, it's no longer an original unit.. Totally fine, but if you are bothering to update, you may as well get the best functionality you can. The Blaupunkt has an RGB display that you can tweak to get an exact light colour match to your dials and switches, it has a built in Mic, or a remote Mic, the built in is actually very good for the when the top is down as it's protected from the wind, and works very well.
3. The new headunit gives me DAB radio, I installed a small adapter that allows you to use the original aerial for the DAB radio, so nothing needs to be added or modified other than the headunit.
4. It uses the exact same wire loom as the original, plug and play, no mess, no fuss. I have obviously kept the "original" Eurovox, but I can bet pounds to a peanut it'll NEVER see that DIN slot again..
5. The headunit has a USB cable out the back that can very easily be tucked behind the glovebox footwell and left in the net to connect and charge your phone discretely.
6. The BT actually works, flawlessly I might add too, not funny way to select and connect, all as it should with a modern radio.
Thanks for the info Kamil. I'm actually based in Australia but shipping the car in from the UK. But I wouldn't mind contacting this company to see what they can do. Do you know if they have an email address too?
From what I know, when creating a BT connection, they unplug the CD changer cable from the back of the head unit and instead connect the BT emulator and decoder (when you have a fiber optic/D2B system) into the CD changer socket, which is why you end up losing the functionality of the CD changer since it remains unplugged. But what you're saying is that after your BT upgrade, you actually managed to keep the full functionality of your CD changer since the BT connection was routed via the Phone button, is this correct? Is the phone button some after market installation? Where is it found because the Becker unit obviously has not phone button?
You said you still need to pick up the phone on your iPhone screen. Does that mean the only way to answer a call is by using your phone?
The two replacement units mentioned in prior repsones seem to be the go to ones.
If you prefer to keep the original head unit, Becker Audio will retrofit it to support bluetooth. Given I have a low mileage good condition vehicle I think originality is going to become important so that is what I plan on doing with mine.
Hey sp3000, thanks for the detailed info. I'm also from Oz, Melbourne, but shipping the car in from the UK as we speak. I should have it on the road by mid March given that I don't have any issues with compliance and all that jazz. I really want to keep the factory installed head unit as I want to retain the original look. Granted if i modify it by adding a BT connection it's not entirely original, but it still looks the same and the modification is hidden behind the radio. But if i was to change the head unit then the Blaupunkt you've recommended would be the way to go as I'm fairly impressed with its functionality. The real sticking point for me though is the fact that you lose the connection/functionality of the factory subwoofer and amp which is meant to be far more superior than the Blaupunkt inbuilt amp.
Also, from what i know, DAB radios need a DAB specific antenna since you can't get a DAB (digital) signal from a standard analogue antenna such as the ones fitted to the R129. But if i understood correctly, all you had to do was use a plug adaptor and you can now receive both analogue and DAB signals via the existing analogue antenna on the car, is that correct? If you have a link to a similar adaptor, it would help. Thanks
to pick up the call I need to press TEL button (it changes audio source to Bluetooth). Then I’m picking up the call on my iPhone.
almost all the time I’m using BT anyway so it’s not a problem for me.
Eightwood DAB Antenna DAB Splitter SMB Adapter DIN Adapter AM/FM Antenna Signal Amplifier for Car Radio
If you google it, you'll see quite a few options, Amazon AU have them, I bought mine direct from Amazon DE when I bought the headunit, as it was cheaper that way to Australia than from Amazon AU or other options.
You just splice in the power.
As for the BOSE amp and sub, YES it does go through the BOSE, sub amp and all. The Bose setup in our cars uses a speaker level input, not a line level input. That is why the EUROVOX works just fine as the factory fitted option we got here. It's a bog standard ISO connection with speaker outs. Any headunit will connect and use the BOSE amp and sub. I can post the wiring diagram if you like.
They also make passive DAB antenna splitters, but I don't know how well they work, I read that it was best to go with the active one, and it's been very good. I think passive may give you a very weak signal with our antennas.
@sp3000 It's good to know you can still use the Bose sub and amp, And keeping the original antenna by using this nifty little DAB antenna/splitter is a winner. If I can't upgrade the original unit, then I'm heavily leaning towards the Blaupunkt head unit because of these two things. Thanks for the wiring pics, they're clear enough
@kamil.kniczek do you mind giving me the details of the Polish company you mentioned. If you have a link to their business that would be great.
Also, in addition to upgrading your radio to include BT capability, was it also upgraded to play DAB radio? I'm not sure if that is even possible on such old radios but just asking in case it's a thing. Thanks
Last edited by Moonmann; Feb 26, 2026 at 10:44 AM.
