Busting the Bose Bluetooth Myth

Every thread of every Cayman or Boxer forum dealing with connecting aftermarket Bluetooth devices, ipods, etc to a Bose configured car claims that it is not possible to route the output of these devices to the Bose attached speakers without using a Dension, Mobridge etc., MOST Bus interface box. These boxes are relatively expensive and are unnecessary in the case of connecting a Bluetooth device or a Navigation system. I have spent consideralble time reverse engineering the CDR-24 radio pinouts and discovered that by inputing a line level audio signal into pins C7 (+) and C12 (-), that it is possible to make the CDR-24 output this audio signal onto the MOST bus for use by the Bose amplifier . In short by connecting an audio signal to these pins on the radio, you can hear the audio on the Bose speakers (or other speakers connected directly to the CDR-24). The CDR-24 also will control the volume of this signal, just as it does all others. The details follow: C7 and C12 present a 480 ohm impedance input for connecting Telephone Audio In. C12 is not chassis ground, but rather the signal ground for this pair. This signal can be directed through the CDR-24 to the MOST bus (or the speaker outputs on the B connector) and then to the speakers depending on the USER settings configured by the radio’s MENUE button. You can setup 3 independent users/drivers (see the Porsche CDR-24 User Manual) for the vehicle using the MENUE button. The audio parameters of the system, along with the steering configuration (left hand / right hand), CDR-24 front panel LED operation, stereo output mode and behavior of the telephone mute signal can be programmed and saved on a per user basis. The behavior of the telephone mute signal is of most interest. If the USER setting is programmed for “Phone Mute”, then assertion of the telephone mute signal (A3) or pushing the TP button on the radio will simply mute the radio output. If however the USER setting is programmed for “Audio Phone”, then assertion of the telephone mute signal (A3) or pushing the TP button on the radio will cause the differential signal on the C7 / C12 pair to be amplified and passed on to the MOST bus and will be heard through the attached speakers. The USER setting for steering configuration will determine which speakers are used for output of the telephone in signal. Setting DRIVER L, will cause the right hand speakers to be used for telephone output. Setting DRIVER R, will cause the left hand speakers to be used for telephone output. I have tested this with a Parrot Bluetooth phone kit and it works GREAT!! This interface would also be suitable for aftermarket navigation systems as well. Ipod and auxiliary audio sources still need to go through a MOST Bus converter box, if you want to listen in stereo (kinda the point of these devices). I have collected in one PDF document everything I know about the CDR-24 and PCM wiring. I have uploaded it to my personal file area, but can't seem to get to it to do anything with it. If an administrator could help me out and place this in the general files or articles area of the website, I would appreciate it. timbucthree

What he said...

:banana: Awesome. Subscribed. Holding breath for PDF....

When you say you put it into your personal files area what do you mean by that? You can email it to webmaster at planet-9.com and I can put it into the main files section here for you. How large is the PDF?

I feel an electrical award coming on.... :cheers:

You can now find the article at the this link.

Wow. I am impressed.

Thanks. Wish I had known this a year ago. In any case for those interested in just adding aftermarket bluetooth, navs or both, this should solve a big problem and save folks some money. I have not been able to test it, but I believe this will work with the PCM as well.

Subscribing. Would love to see an installation instructions for the Parrott Blutooth setup... Tomasz

Interesting detective work, man! The PCM system's mute functionality seems to be a bit different from the CDR-24, from what I remember though. That and I have no idea if the pinouts are the same on the harness. Don't have any schematics in front of me right now to say much.

Timbucthree, Excellent work! Thanks for sharing, I've long felt that this kind of functionality was buried in there somewhere, given that all of our cars have the TP (Mute) button. This will probably push me to go ahead and install bluetooth.

Parrot interface is pretty simple. Before connecting to the CDR-24 you must modify the stock Parrot harness. On the A connector do the following: 1 - Parrot has the +12V Battery and +12V Switched signal lines reversed, this will solve the problem. Open up the two inline fuse housings (orange wire and red wire). 2 - Swap the connections so that orange wire from radio passes thru a fuse to the red wire leading to the Parrot Mute box; and the red wire from radio passes thru a fuse to the orange wire leading to the Parrot Mute box. 3 - Vampire clip the signal line coming from A5 to A7 near the connector end that will plug into the CDR-24. A7 is now your switched 12V input to the Parrot Mute box. The A7 wire is red. 4 - Connect the mute pin coming from the Parrot Mute box to the Parrot A connector to be plugged into the CDR-24. Connect the mute pin to pin A3 (known as Mute 3 on the Parrot A connector). 5 - The biggest problem now confronts you, you need two pins to insert into the C connector to make your audio in connection. I will post a link to a source to purchase these pins tomorrow, you can't get them at radio shack. You can order them over the Internet. 6 - once you have the pins, you will need to crimp them and then solder them to the "Line In 1+" signal line (another red wire) and to the "Line In 1-" signal line (a black wire) on the Parrot harness. 7 - disconnect the C connector from the back of the CDR-24 8 - insert the pin connected to the "Line In 1+" into the C connector at C7. 9 - insert the pin connected to the "Line In 1-" into the C connector at C12. Ignore the B connectors on the Parrot Harness, you do not need them in a Bose installation. In a non- Bose installation you don't need to follow steps 5-9 above, use the B connectors per the Parrot instructions. Steps 1-4 are always necessary. Connect the A connectors up as instructed by Parrot. Reconnect the Porsche C connector removed in step 7. Understand this procedure is the lowest cost, but requires that you modify the Porsche C connector harness. A less intrusive, but more expensive solution is to purchase 1 male and 1 female ISO connector and associated pins. Make a harness extension that wires C1 M to C1 F, C2 M to C2 F, C4 M to C4 F and C20 M to C20 F. This is just a pass thru cable. Then insert the C7 and C12 signals into the plug end of this harness. Now plug the plug end of this harness into the radio C connector and the Porsche C connector from the Porsche harness into the other end of the pass thru harness. This results in an installation that does not modify any Porsche wiring and is very easy to remove. This is my preferred method. Hope this helps. Please note that the wire colors given for the Parrot harness are from their LS3400 and LS3200 kits. Their newer kits may have changed these wire colors, but I doubt it. The signal lines will exist in all Parrot hands free kits I am aware of. timbucthree

actually, quite a few people at caymanclub have parrot bluetooth systems in thier car. I installed a parrot and a iPod adapter within a month of so of buyint my 2006 CS. I wrote an article on it a year or two ago but I admit to taking it down so I could re-write it and then forgot about it. Question though, how does it work while you are driving? Mine worked perfect at idle but no one could hear me when I was driving. It seemed to be a clear microphone issue but I never did find a more direction mic to try.

Works great. The microphone is not a problem, never has been, even when driving at speed. The problem has always been getting the sound to come out of the Bose speakers without cutting directly into a speaker wire harness or going with the expense of a MOST bus converter box. I have only noticed two differences - 1 - the Bose speakers produce much better sound quality for the call than did the external 2" CB speaker I had used for the first year my system was in use. You can read about my initial install at this link. 2 - the initial speech, first few words, of any Parrot Menu announcement is clipped off because the delay between assertion of the mute signal and response of the CDR-24. This is not a big problem as the Parrot spoken menus aren't really critical to operation of the system. When using an external speaker, the external speaker delivers the Parrot menu while the CDR-24 is still playing music before responding to the mute signal assertion. You trade one small issue for another. My Parrot microphone is placed on the steering column, between the two Bose feedback microphones. This is a single microphone unit.

Wow thank you so much, your PDF wiring connection pinout diagram for the CDR-24 is very useful! I have a Boxster 2004 with the CDR-23 and the pinout is the SAME, as far as I can tell / need to know.

Amazing thread that represents a great contribution to the library of data here. Thank you Timbucthree... :cheers:

Thanks for all of the great work and it helps a lot, but I'm still struggling a bit. I'm trying to hook up my iPhone 3GS as a "phone" but also to use it as a navigation system using the new Navigon application. I have the phone nicely installed using a Kuda kit and a Carcomm mount. I built a wiring harness extender to allow me to quickly tap into C7 and C12. I've installed everything and have programmed the CDR-24 via the Menue button to put it into "Audio PH" mode. Everything should work, but there is no sound coming from the iPhone through the speaker when I hit the TP button. Just MUTE. I tested the harness and the circuit is OK going into C7 and into C12. From the audio input from the harness, I measured the impedance and it is 470 ohm (which is in range from what is documented). Everything looks OK but no audio. The only thing that I can think, is that the A3 Telephone Mute Input signal must be connected but according to the documentation, this seems optional as the TP button can be used instead. Any ideas?

You need to assert the A3 mute I believe. The car kits I am familiar with do. The TP mute button does not work the same way as assertion of A3. It mutes period, no ifs ands or buts. Just ground the A3 signal and see if you get sound from the iPhone . I am pretty sure that you will. timbucthree

In follow-up to my own post. A3, telephone mute must be grounded for C7/C12 to work. I connected the line to A3 and manually grounded it out; viola, the audio from the iPhone comes through. Thus, the documentation that is provided is a great and incredibility useful but not correct. The PDF states "If however the USER setting is programmed for "Audio Phone", then assertion of the telephone mute signal (A3) or pushing the TP button on the radio will cause the differential signal on the C7/C12 pair to be amplified and passed through the MOST bus...." is not correct. The correct statement is: "If however the USER setting is programmed for "Audio Phone", then assertion of the telephone mute signal (A3) on the radio will cause the differential signal on the C7/C12 pair to be amplified and passed through the MOST bus...." Notice that the TP button does not play a role in amplification and pass through of the C7/C12 signal. I tried all of the combinations and this is what I found. The TP switch really does not do much but mute whatever audio is going through the amplifier. The A3 line that when asserted (i.e., grounded) is the only way to control the muting and the passing of the telephone (or Navigation) audio through the system. If the CDR-24 is configured in "Audio PH", then the A3 grounding will play the Phone Audio through the speakers. If the CDR-24 is the in the "Phone Mute" mode, then the grounding of A3 simply mutes the radio and no audio from the phone is played into the speakers. Thus, the next piece of my puzzle is to figure out how to control the A3 line with an iPhone that does not have an radio mute control signal. My thought is to use a standard audio controlled switch as a relay to take A3 to ground. What I mean by this, is that the switch takes in an audio signal and if it is live (i.e., audio is present), it trips a relay that takes the A3 line to ground. I think that I've found one that costs about $20 and I have a query into the manufacturer to verify that it will work. If it does, I will post my results. ---------- I tried a solution which used an audio controlled relay. I've enclosed the circuit in a box and have installed it. It works but not that well. The relay is not really designed for work in a car and is too sensitive and trips going over bumps in the road. Not sure what I will try next . I really like having my iPhone in a cradle and using the turn-by-turn Navigation using the Navigon application. However, it looks like I need to look at some new options. These include: 1. a separate speaker for the iPhone - takes up space and does not mute the phone 2. a dedicated navigation system - will require a mute function 3. a bluetooth system that will work the mute function Any other ideas?

Pnerger, I will update the PDF. You are correct it was worded incorrectly. Your Iphone relay solution is what I would have suggested. The only problem is that the CDR-24 has a bit of a delay in responding to ascertion of the mute signal.

Tim, Thanks for the post... your time is appreciated:thanks:

Hi Gents. Please excuse my electrical ignorance. This thread seems to mainly refer to bluetooth phone connectivity (if I understand it). I have the CDR-24 head unit, without PCM , and with Bose . Could I, or someone, use this info to connect my Ipod ? I do not need phone connectivity. Thanks.

The CDR24 only has mono capability using the interface described. This is sufficient for handling phone calls. If you are happy with listening to your ipod in mono, this would work. I suspect like most folks, you would prefer stereo. timbucthree

Thank You. You are correct - I like stereo.

I just wanted to thank Timbucthree for posting the info here. I just installed a Parrot CK3100 in my '08 Boxster with the CDR and Bose -- and the info in this thread came in very helpful. I do have one question. I've noticed that when I'm on a call that the sound is fine while the person on the other end of the line is talking. But when I'm talking and they are silent, I hear what sounds like the volume level being raised -- the speaker goes from being silent to making a soft hissing sound (like you were turning the volume up on a stereo with no source playing). I've adjusted the Parrot volume level to its lowest setting and it still happens. Any ideas on what's going on?

Hi All - This thread is older but thought I would chime in. I make the wiring harnesses for the Parrot kits - www.quickconnectproducts.com (QCP) and the above is very helpful. It does deserve an award! If you have hissing or if the audio is too loud, it likely means that the radio input is looking for low level audio. So if using the Parrot CK3100, use the brown and green low level line output wires as your feed. If you have the CK3000, simply insert a line output converter (LOC) inline (available at most car audio shops) in the 2 audio leads. One other thing if you will allow me to do a mini promo. The above is great for cell calls since the input is "Mono" - but we have a new device to integrate a full blown Parrot stereo bluetooth handsfree/music kit like the MKi9000, MKi9100 or MKi9200 into the vehicle provided it has the fiberoptic MOST amp. See below for our new interface. Our new QCFiber fiberoptic MOST interface for the MKi kit simply daisy chains with the orange fiber cable behind the radio and speaks digitally (and directly) with the MOST amplifier in compatible 2004+ Audi, BMW, Mercedes, Land Rover, Porsche and Volvo cars. Simply connect to the fiber ring, to 12V, and plug in the Parrot blue brain - the entire interface is installed in minutes! The audio path from our interface remains all digital and the radio's controls all remain active for the Parrot including volume, balance, fader, bass, and treble. You can do music streaming of all kinds including Pandora wirelessly from your phone. Or load up a USB thumb drive or SDCard with music in directories for a voice activated music storehouse. No data appears on the radio (just the Parrot screen) but the Parrot features, sound quality, and very reasonable price for this advanced interface more than make up for this. Plus, it is the data display feature of such units as Dension, mOBridge and others that can cause some incompatibilities. No reprogramming of your car's computer is necessary and you can have the CD Changer still working if you have one. Our interface simply works - as long as the car has a compatible MOST amplifier. Verify that the car has the MOST amp and not just a fiber CD Changer and it should work in nearly every 2005+ model of the car brands listed. This is a great solution if you have the CDR24 and Bose (non PCM cars) for example. PM me for more info and a discounted price (provide your radio type, year and model). I've just inquired about Planet-9 sponsorship so that QCP can hopefully offer a group buy in the future. Howard

This is very interesting, but the interface will not work with cars that have PCM ?

Hi there, I know this is an old thread... So, your adapter is almost $300? and you sell the Parrot for $225? Is that right? So a total of about $525? Do you have any photos of the installation and finished product? Thanks, Franny

Hi. You would need the QCFiberA-MK fiberoptic interface and one of the Parrot MKi kits. I don't have installation pics but you can see the Parrot kits on the parrot.com website. The MKi9000 does not have a screen so the wireless remote is all you would see in the car.

Hello, I am new to Porsche & this forum. Recently purchased an '07 Boxster S with the std CDR-24 radio, with the " BOSE High End Sound Package" subwoofer, etc. What is the latest on Radio, Bluetooth, etc. options that can be installed by myself? Radio options? Can I use the existing BOSE amp , fiber? Thanks in advance for your comments and help. Bob

I am in the same boat, though with a 2006 BS. So far it seems the options are as follows: Dension Gateway 500 - good, but no bluetooth https://www.bumperplugs.com/index.php?route=product/product&product_id=123 Becker offers a direct connect option - cheap and effective, but MONO aux_input Mobridge - aux input and iPod Vehicle Compatibility Guide | mObridge NavTV - separate (I think) aux input and iPod offerings NAV-TV Corporation: MOSTAUXPOR AUxillary Audio Input for Porsche Bose Audio System Suncoast has a kit (Eurospeed??) that will let you hook an aftermarket HU to the BOSE amp Aftermarket Radio Installation Kit orsche Parts & Porsche Accessories - Wholesale Porsche Parts & Tequipment - Cayman Panamera Cayenn Finally there is the DIY-ish option found in this thread, which, seems tempting although MONO is something to be avoided in my opinion. If someone whom is more electrically inclined can weigh in it would be appreciated. I don't want to speak for other, but all I care about is a stereo option for bluetooth audio. Thanks, Carlton