[sniffer]

So, I have investigated the potential options relating to getting seemless IPod control through my IDrive (CCC) system.

After much research the Dension Gateway 500 system seems to be the best option.

This is compared to:

1. Phone jack, leaving as is

2. BMW IPod Interface Retrofit

3. mObridge

We know the BMW kit has limitations, including slow operation with an IPod with any number of artists / titles on it. Also, it has limited compatiibility with newer Applie units to charge. It also does not offer a USB function.

The Dension does offer USB. With The Dension I have the potential to plug in USB sticks or external hard discs full of mp3's. I can then navigate around this using the BMW IDrive system.

The Dension offers slightly better functionality than the mObridge from the research I have done. It also works out slightly cheaper if you install it yourself.

With the Dension, you are apparanatly able to drill down and search artist / title / etc by inputting the first letters and the unit narrows down the search results. You are not able to input first letter(s) and start filtering the results with the mObridge.

So, I purchased my brand new Dension Gateway 500 from In Car Music in Leyton, East London for £300, all in.

Today I installed it, my car does not have a CD changer and has never had one. Installation is pretty simple, but I had some issues with the MOST bus, so wanted to outline how this works to help others.

The information I used was:

Dension Install into an E90

http://www.e90post.com/forums/showthread.php?t=84125

BMW Instructions for Retrofit CD Changer

http://www.e90post.com/forums/showthread.php?t=4194

Overview of BMW MOST BUS

MOST is BMW's optical fiber network used for entertainment and communications systems. It is used as a system to connect together a few different systems in the car. . .such as Bluetooth, CD Changer, DAB radio, etc.

It works in a RING. Therefore each unit connected onto the MOST network has an input and output. Light goes into the unit and out of the unit. If you unplug a MOST connector somewhere in the ring, the ring is broken, light can no longer flow around the ring and all systems on the ring will therefore be down.

Installation

I chose to install my Dension into the LHS of the boot, where the CD changer should be. I will then put the bracket supplied with the Dension kit onto the plastic tray on top of this gubbins, meaning I will easily be able to access my IPod to remove it from the car.

To install it, you need to remove the LHS boot liner. Here you will find the CD changer wiring, installed in a padded sleeve, which is velcro fastened so you can simply undo it. In here you will see the CD changer connector. It consists of a MOST connector, which is two optical fibers (light in and light out). You will also see a power connector block on the side which is simply 12v and ground.

If you inspect the CD changer connector, you are able to press a plastic nobble and remove the power connector from the side of the connector. If you then look at the rear of the connector, where the MOST fiber connector is going in, if you press the tongue down with a small flat blade, you can withdraw the MOST connector from the CD changer connector.

You can then plug the Dension Gateway 500 MOST connector into the CD changer connector. (see Dension instructions for which one is the correct MOST connector on the Dension).

You then need to power the Dension Gateway 500. I took power from my Vibe Litebox Stereo 4 amplifier, which sits just below the CD changer bay.

So you now have the Dension with MOST connector plugged in and power. Put the unit into "invisible" mode. Dension call this service mode. Effectively what it does is simply make the Dension put the light received down the MOST input back out the output. Therefore the Dension is invisible on the MOST bus.

So, now we have the Dension Gateway 500 installed into the car, we need to connect the CD changer MOST bus optics up in the MOST bus connector block. On my car (2007 E92) the MOST bus connector block is located behind the LHS rear seat side panel.

It is explained in a diagram within the CD changer instructions, how to add the CD changer into the MOST bus loop. However, I wanted to take this opportunity to explain better how I believe this system works:

[sniffer]

OK, what I am trying to show in my pictures are where the MOST Bus connector block is, what it actually is and how it works.

I have taken pictures of the bottom of the block and the top of the block. There are two blocks as you can see in my last picture of this post. The top block is for connectors which are not in the ring, e.g. the CD changer. The MOST in and MOST out for this device therefore need to be moved over into the live ring, which is the bottom MOST bus block connector.

The way I understand this works is at the bottom, port 1 is the input from the central CCC computer / head unit.

You therefore have an input and output for each device in the MOST ring, the inputs are at the top of the connector. If the connector is plugged into the device and the device functioning properly, will allow light to travel back down the output side.

You can see from my pictures, I have been busy with the electrical tape again This was because I had problems getting this to work so logically worked out what was what.

My coding was as follows:

Black CCC input / output (the daddy)

Yellow CD Changer input / output

Red Bluetooth input / output

So hopefully, what you can see in my photos is as follows:

MOST output from CCC (the Daddy) - Bottom of connector, furthest to right

LIGHT GOES TO:

MOST input to CD Changer - Top of connector, furthest to right

LIGHT GOES TO:

MOST output from CD changer - Bottom of connector, second from right

LIGHT GOES TO:

MOST input to Bluetooth - Top of connector, second from right

LIGHT GOES TO:

MOST output from Bluetooth - Bottom of connector, third from right

LIGHT GOES TO:

Unknown MOST input - possibly TV - Top of connector, third from right

LIGHT GOES TO:

Unknown MOST output - possibly TV - Bottom of connector, fourth from right

LIGHT GOES TO:

MOST input from CCC (the Daddy) - Top of connector, fourth from right

So what we have therefore, is a completely connected loop, with the light passing through all modules / devices.

[sniffer]

So, when I eventually got how the MOST connector block and MOST bus system actually works, it was easy.

I therefore currently have the Dension Gateway 500 installed in the car and installed on the MOST bus.

However, it does not work as yet because I need to take the car to be coded by a company who has the necessary equipment. This simply tells the CCC (head unit) to talk to what it sees as a CD changer (Dension).

To get the MOST connectors open, you simply use a flat bladed screwdriver to prise either side off and the cover comes off.

Once you have the cover open, to remove a MOST fiber, use a small flat blade to GENTLY and CAREFULLY lift the tongues in the middle which hold the fiber into the connector block, while at the samel time pulling gently on the fiber and it will come out.

I busted one of the tongues on my MOST connector block by being a little too vigorous with the tongue lifting. All I did, was swap the connector blocks over and simply used the one which was previously on top, holding the CD changer MOST BUS in and out. I was then more careful.

[Dr Dave]

Now this is great stuff - as when I fitted my CD Changer, upon starting the car up my SOS system flagged up an error.

I fitted the MOST fibres as per the BMW CDC instructions. I put it down to the car not having been coded to 'see' the CDC.

Now I will look at it again, thanks to your superb work Sniffer!

[sniffer]

Hello Dave,

I had loads of SOS errors when I was playing around with this today. The SOS errors on my car meant the Bluetooth was off the MOST bus. . .

I ended up shining light down the MOST connectors for the CD changer and the Bluetooth so I could work out what was going on. . .from this I was able to see the daisy chain layout of the system, the "loop" if you like and how all the modules fit into it.

The order of a module in the BUS does not make any difference as I can see it. You could put the CD changer after the Bluetooth or whatever, provided it was interfaced into the ring in such a way that you have light going all the way round and coming out the final stage back to the CCC.

The problem I had was that I had effectively broken the MOST bus ring because I did not have my Dension powered on. . . . . . .

It took me a while but after working out what was what and plugging the fibers together without using the MOST block (BMW have been very considerate for this) so you can plug any of the fibers from the bottom into ones at the top, or any "input" into any "output". They are effectively male and female. I eventually worked it out and then just put them all back into the connector block in the order I worked out with them plugged together outside the connector.

I sat in the back seat, mucking around and cycling the ignition on and off. You could see as soon as something was wrong as you got the SOS and if you went into the comms on IDrive it said please install a mobile phone (by this they mean Bluetooth module I believe) and there were no options available.

I played about with the ignition on and off and didn't have any issues. I think the system is pretty intelligent, so I dont think you can bust anything. If you muck the ring up, it will retry comms at random intervals. I however found it easier to simply cycle the start button to shut it all off then start it up again with a different configuration.

I think the biggest PITA danger with playing about with this is if you are heavy handed and damaged a fiber. Obviously, they look to be much more hardy than the networking ones I am used to, but if you bent one too much, you could snap the glass inside and then you are knackered. Particularly nasty if you damaged one of the daddy ones going to or from the CCC.

So as to why you are getting SOS errors??? Perhaps the CD changer is not getting power? Is it defo the right one for the car because I would expect it to return the light back and you not get theses errors. . . . .

[gIzzE]

For anyone else doing the Dension install it is far easier to simply take the most connector apart in the back of the head unit and connect the most cables there, and then crimp the 12v and ground to the same connector.

You can then tuck the unit down behind the trim in the passenger footwell.

This takes around 20 minutes including running the cable to the centre console and the aux/service switch to the glove box.

[sniffer]

OK, so had car coded today. Many thanks to:

http://www.dandtwise.co.uk/

They used the Autologic diagnostic system to code my car. Did it while I waited, as has been posted elsewhere, there was an option within the Autologic system for Dension.

Really impressed so far with the usability and speed of the system. Sound quality is obviously excellent, but having the ability to drill into artists or albums by using the first letter of the name is a really nice feature.

Some photos:

[sniffer]

More photos:

[jonnydrama]

Thanks for this post, it helped me understand the MOST bus no end.

As I have professional media pack with no TV I only had 2 fibre optic cables at present, with 1 to add into the loop for the cd changer. I drew out what I expected the ring to be like and it worked first time. For anyone doing this with a similar setup add the bottom cd changer fibre optic cable to location 3. At the upper end put the fibre optic cable currently at location 1 into location 3 and the cd changer cable into location 1.

[sylonien]

Can you play video from the iPod with this Dension?

[TorchE92M]

sorry to dig up an old thread but with regards to the service MOST connector in the glovebox did you need to loop this to get the dension working ?
in the dension troubleshooting guide it states that this should be looped but im having trouble with my MOST linking as I cannot seem to get the loop completed

[TorchE92M]

tackled this again today and finally got it working

[Tigamilla]

Thanks for this wonderful post - was a massive help hooking up the MOST bus