Gateway 500 for MOST - not ready for prime time?

[Skylaw]

NOTE: I changed the subject line of this post on June 20; it was originally "Not ready for prime time?" because of the poor instructions in the installation manual, and a less than satisfactory user manual detracting from otherwise good hardware. With Firmware update 2.02 and a new user manual, significant improvements have been made; the installation manual (dated "after 03/13/07") still needs revision, so I hope the post below will help until the revision is in place.

I installed a Dension Gateway 500 (GW 500) for MOST bus in my 2005 S500 (U.S. spec). Below, I document the installation from removing the COMAND unit, including the wood fascia; locating and running the three copper cables from the console to the GW 500 location; locating the GW 500 device; and connecting it to the fiber optic ring. This was a difficult first-time project. I accept no liability for damage to your car or to your GW 500 if you attempt it. In addition, I do not repeat the steps of the Dension supplied Instruction or User Guides, but supplement them. You will have to use the installation guide and user guide. In addition, I am familiar with my own '05 W220 because I have done this installation; I am not familiar with other models in detail, and cannot answer specific questions about them. I hope there is sufficient detail below to carry over to other models.

Most of you will already know that the GW 500 is designed to allow an iPod to replace the CD Changer (CDC) on the fiber optic bus, but allow switching back to the CDC if desired. On COMAND-equipped cars, it will display menus as well as song title, playlist name, and play time on the COMAND display; and track information on the instrument cluster multifunction display.

Unfortunately, at this time, the GW 500 is not working in my car. Though properly installed it will not replace my CD changer on the fiber optic bus. At this time I do not know if it is because of the unclear fiber optic installation instructions, or a defective unit. (NOTE: See post #5 below; got it working).

I located the iPod, USB, and AUX connections and the CDC/GW500 mode selector switch in the console, and the GW 500 unit behind the ashtray in the COMAND console space. The cables (copper and fiber optic) supplied require an installation in the passenger compartment; they are long enough if you locate the input cables in the glove compartment, but are barely long enough for a console installation in an S-Class. They truly need to be at least 6 inches longer.

REMOVE THE COMAND UNIT

The COMAND unit is removed by placing the car in “Drive” (set the parking brake); pulling the ashtray out; removing two screws behind the wood fascia with a #20 Star driver; then fully removing the ashtray (disconnecting the cigarette lighter connector at the back). See first photo.

With the ash tray and screws removed, the air conditioning controls slide right out; I reached under it and gently pulled it from behind. Only two clips hold it after removing the screws. See second photo.

After removing the ashtray and A/C controls, you may place the shift lever in Park. The wood fascia for the ashtray and A/C controls come out with the units, and do not have to be separately removed. All of the wood fascia are sturdy; they are mounted to a metal or heavy plastic backing, and the only special care needed is not to scratch them. I did not disconnect the A/C unit from its harness, but let it hang to the right of the console.

Next, insert a small screwdriver or knife (covered with tape if you wish) at a lower corner of the upper wood fascia, above the COMAND unit, and pry it outward. The fascia is held in only by sturdy plastic clips and will pull out easily. In the photo below, the clips for the A/C controls and the removed upper fascia (resting atop the A/C control unit) are visible. See third photo.

Removing the A/C controls and upper fascia reveal the four Star screws (#20 driver) at the corners of the COMAND unit that hold it in. At this point I went on to installing the iPod, USB, and AUX input/GW 500 selector switch in the console, and routing the wires to the now-open space below the COMAND unit.

However, for purposes of illustration, the last photo shows the back of the removed COMAND 2.0. The MOST version has only five connections: Two fiber optic leads (orange), a +12 volt wire (red/yellow), a brown wire (ground), and a blue/black wire (I believe the dimmer control for lighting the buttons on the front of the unit). That’s all there is for the MOST unit. We’ll get back to the connections made here, later.

[Skylaw]

I wanted all of the input connections and the mode selector switch in the console. These may be placed in the glove compartment far more easily – all, or in any combination. However, I elected to do it the hard way, for future convenience. The first photo shows my upper console compartments (phone and storage), open. The false floor is held in place by three Star screws (#10 driver), two of which are under rubber covers.

I removed the false floor to reveal the MHI phone wiring and Tele-Aid button connector, and disconnected Tele-Aid buttons by prying the side with the small retention clip. The MHI wiring slips out of a slot in the bottom of the false floor (on the back), and need not be disconnected. See second photo, below.

I drilled a hole in the back wall of the false floor using a ½ inch drill bit, and then had to enlarge it to allow the USB connector and 9-pin iPod connectors to pass. I ground the two side flanges off of the AUX/mode selector, and used the two small screws that hold the back panel onto the switch to affix it to the back wall of the false floor as well, as shown in the center photo below. I also cut a notch below the mode selector to allow its wiring to pass. Inside the tiny hole in the Aux/mode selector in the center photo is the reset button.

I also drilled a ½ inch hole in the back wall of the lower part of the console, and enlarged it to allow the connectors to pass. The hole is just below the curve of the black wires. This hole lines up with the similar hole in the false floor. Careful when drilling, so as not to hit your console exterior! 4th photo below.

Below the holes, by the hinge, is a small rectangular tab, which snaps out (5th photo). It is large enough to allow each connector to pass, and be fed to the console floor. I fed the connectors through the two holes drilled, and through the hole for the removed tab. I could not thread the wires through the hinge itself because the space is already occupied by other wiring.

In the 5th photo, the hole exposed by removing the tab is shown with a tan wire passing through it. I started to use this wire as a “fish” but found the connectors would drop straight down to the console floor easily enough (with a little coaxing). I had also removed the console light fixture as a potential aid to fishing the connectors, but this turned out to be unnecessary.

[Skylaw]

Access to the console floor is by removal of the back panel, below the rear A/C vents. Pry it from the upper corners until it pops out slightly; then lift it up. Pull the bundled wires and connectors for the MHI and Tele-Aid buttons out slightly to gain clearance to retrieve the GW 500 connector cables, which can be see at the left side of the console in the first photo below.

Before feeding the connector wires forward, I reinstalled the false floor into the console, and mounted the USB connector clip where I wanted it, to be sure not to pull the wires too far forward, and to ensure enough slack to open and close the console.

One may be tempted not to drill the holes as I illustrated, but to feed the wires over the lip on the back of the console and then into the hinge hole. Doing this will push the console lid forward when closed, making it difficult to open. A little thought will reveal how I know this. Drill the holes. My console setup is shown in the second photo, below.

By repositioning the driver’s seat several times, you can tuck the connector wires under the left side of the console until you reach the front part of the console. Pull the carpeting out as shown in the third photo below, and feed the connectors into the space behind the (removed) ashtray, under the COMAND unit.

The third photo below shows the carpeting pulled back at the front of the console, just ahead of the driver’s seat. The dark space at the left of my hand is an alternate spot to place the GW 500 box, if you wish – it will cause a very slight bulge, but is easier than working in the console space. Of course, I did it the hard way. The connectors are fed through a small space just above my thumb (which could be used to feed the power and fiber optic leads out, if you place the unit outside the console, under the carpet).

Once the fiber optic and power connections are made, the connectors will be inserted into the GW 500 unit as shown in the fourth photo below. Because the connector wires from the console are short, I could not place the GW 500 unit high in the area behind the COMAND unit, where there is plenty of space. Instead I put it atop the airbag control unit (with the orange label), slid it into a space that is just above and behind the airbag control, and affixed it with industrial-strength Velcro (barely visible toward the back of the airbag unit). Care MUST be taken to avoid crushing or overly bending the fiber optic leads plugged into the left side of the GW 500 unit when positioning it here - but there is just enough space to make it work. From left to right, the USB input is just under the orange fiber optic lead; then the 9-pin iPod input; an unused and disabled 9-pin socket; and the AUX/mode selector input just beneath the orange fiber optic cable on the right.

[Skylaw]

Before hooking up the connectors from the console, one should make the fiber optic and power connections to the GW 500, because the short length of wires from the console leaves little to work with. Now for the really fun part. First, remove the COMAND unit as discussed above. After removing the four screws (#20 Star driver), it just slides out, Do not kink the orange fiber optic leads – doing so can ruin them.

The Dension installation guide (available on the Dension support site, Dension - Support) is very badly written. Its diagrams are small, and the text is inadequate. The diagrams for fiber optics, which show the light path, indicate that the GW 500 is to be installed immediately ahead of the CD changer in the fiber optic ring. This is easy to do with a CDC mounted in the passenger compartment; but for a trunk-mounted CDC, it becomes much more difficult. The text does not address the positioning of the GW 500 in the MOST ring at all. Therefore I connected it ahead of the CDC in the ring, but not immediately adjacent to it, because no work must be done in the trunk that way. More below.

One must be very careful to connect the fiber optic leads in accordance with the direction of light travel; arrows are molded into the ends of the connectors showing the direction.

On the back of the COMAND unit there is a single large connector with both the power wires and the fiber optic leads. Remove the connector by pushing down on a spring release at the top center of the connector as shown in the first photo below.

Once the large connector is out, release the tab on the left side of it to release the smaller fiber optic connector, shown in the second photo below. Note the arrows at the end of the connector.

On the side of the connector with the arrows are two slits; after removing the small blue retaining plug, insert a fine blade or screwdriver tip, twist slightly to spread it, and gently pull the fiber optic lead out - see third photo, below. For my installation, I disconnected the output lead from the COMAND unit in order to insert the GW 500 ahead of the CD changer in the fiber optic loop. Then placing fiber optic leads into the connectors, push in gently until hearing a slight "snap" then replace the blue retaining plug.

Here is one place things get complicated. The fiber optic diagrams showing connection of the GW 500 directly to the CD changer in the installation guide are probably OK (though the text tells you very little) if you have a CDC in the passenger compartment (probably in the glove compartment). In that setup, breaking the fiber optic loop at the CDC places the GW 500 immediately before the CDC in the fiber optic loop. However, this diagram is practical only for CD changers mounted in the passenger compartment. Follow the rest of the diagrams in the guide to complete the connections.

Here's why it isn't ready for prime time. The diagrams don't work for a trunk-mounted CDC. Unfortunately, for a trunk-mounted CDC, the only place to put the GW 500 is either with the light coming out of the COMAND unit, or going into it. This does not allow placement of the GW 500 in the fiber optic ring immediately before the CDC. The installation guide is silent regarding this physical setup (GW 500 immediately before the CDC); only the diagrams suggest it. Placing the GW 500 on the output side of the COMAND unit inserts the GW 500 before the CDC, but not adjacent to it. Placing it on the input side places the GW 500 after the CDC. And right now, with my GW 500 inserted before the CDC, but not immediately before it, my GW 500 does not work!! It also won't work if installed on the input side to the COMAND unit (after the CDC). I tried. (NOTE: See post #5 below. Suspicions correct - the GW 500 must immediately precede the CDC in the fiber optic loop in order to work).

The fiber optic connections to the GW 500 unit are in fact simple, but the illustrations are poor. What they (and the text) fail to tell you is that a protective cover (with holes, no less) that looks like a connector but will not fit any of the connectors supplied, is installed in the fiber optic socket of the GW 500 box. This protector must be removed before any fiber connections can be made to the box. Once that is done, the rest of the connections become fairly easy to follow. You use a 2-piece socket - a larger part fits into the GW 500 box, and a fiber optic plug then fits into that.

Despite all wiring and fiber optic leads being properly installed and connected, and checked and rechecked as correct, the GW 500 starts my iPod up, but does not replace the CDC on the fiber optic bus. The iPod starts up and begins to show the Dension intro pages; but then it starts playing the last song I was playing before starting up. The CDC remains connected, plays over the audio system, and displays in the COMAND screen, The iPod does not. I am informed by forum contributor Rob13572468 that this problem has occurred for him in GW 500 MOST installations, and may require removing and reconnecting fiber optics in the trunk so that the GW 500 and CDC fall into the right sequence. Rob is researching exactly which connectors to move in my car – the physical connection sequence may or may not match the fiber optic ring diagrams in the phone bulletins on Paul H. Dick’s site (http://home.earthlink.net/~phdwebsit...bulletins.htm). If they do, the solution is to switch the F/O connections (not power or anything else) between the Voice Control Module and the CD changer, which would put the GW 500 in the right sequence, immediately ahead of the CDC in the fiber optic ring. A real pain!! MORE TO COME.

The last thing to do is to tap into unswitched 12v power and ground wires – either those going to the COMAND unit, or by adding a fuse holder on the dashboard panel and tapping into ground. To do the latter, run the power wires to the front fuse panel and use one of the unused fuse slots and also connect to the ground point in the kick panel (there is a 10 mm bolt with ground wires terminating there). (Thanks to Rob13572468 for that information). The supplied power wires are long enough to do this. Unswitched power is required to allow charging for up to 2 hours after the ignition or head unit is switched off. Then, position the GW 500 so that there is clearance for the ashtray, gently place the fiber optic leads so they are not bent tightly or kinked (photo, lower right), and button everything back up.

So there it is. At this point I would proudly show the iPod illuminated and playing, with its ID3 Tag info (playlist name and song title, and elapsed time) displayed on the COMAND screen, and with the track number on the multifunction display. I might even show the Dension menu first page, with eight display options, on the COMAND display. But, alas, I can’t.

The user guide has a procedure for restarting the MOST bus after you change the position of the mode selector switch. The user guide also points out the location of a Reset button on the Aux/Mode Select unit, ansd says to use it during a troubleshooting process but provides no information on what it does. So far, however, using both has not gotten my system working.

As I said, not ready for prime time, mostly for the deficient installation guide, and also for the too-short copper wire connectors. If indeed the fiber optic connections must be rearranged in the trunk, information on which ones to move would be helpful; there is absolutely nothing addressed, and one can glean the need to do this only from the tiny and sketchy diagrams. Not having the unit work after nearly $500 spent on it is vexatious, to say the least.

I continue to work with the vendor, and with Rob. I cannot tell if my GW 500 is defective or if the bothersome need for switching of the fiber optic connections in the trunk is the problem. My unit came with firmware version 1.05, the latest, installed; but if you need to update, you can get it from the Dension support center at Dension Support Center. I’ll keep you posted, and post more pics of the fiber optic connections when I get it working.

[Skylaw]

Thanks to the assistance of Rob13572468, we confirmed that indeed the GW 500 must be installed immediately ahead of and adjacent to the CD Changer in the fiber optic loop. On his recommendation, I swapped the fiber optic connections between the Voice Control System module and the CD Changer in the trunk. This had the effect of placing the GW 500 directly after the COMAND unit and immediately before the CDC, in the loop (see diagrams without Sirius, below). With that done, then selecting the "iPod" position on the mode selector, and following the procedure to shut down and re-start the MOST bus (turn off COMAND, turn off ignition, remove key, wait approximately 2 minutes, then insert key, turn on ignition, then turn on COMAND), the GW 500 worked!!

Note: In cars with trunk mounted CDCs and also with OE Sirius installation, swap the fiber optic connections between the CDC and the Sirius module in the trunk. See diagrams for MOST with Sirius below.

The MOST bus, unlike the D2B bus, uses a signal in the fiber optic path to "wake up" the equipment on the loop (D2B uses a copper wire for wake-up). The GW 500 is most likely designed to intercept this signal for the CDC, thus keeping the CDC from waking up, and places itself and whatever input is connected to it (iPod, USB device, or AUX) on the loop. When the GW 500 is not immediately adjacent to and prior to the CDC, its ability to keep the CDC "asleep" is intercepted or interfered with by whatever follows the GW 500 on the loop, and the CD Changer wakes up and enters the loop. My best guess, anyway.

I did some photo documentation of the switch of the fiber optics in the trunk. It was not a fun job. I'll try to post it tonight or tomorrow.

Bottom line so far: The GW 500 works, and the sound quality from the iPod is wonderful (especially since most of the music is stored in high quality formats - not mp3). I do get song title information and elapsed time on the COMAND display (YAY!), but must do more study in the user manual and play with the system a bit more to understand the menu functions better. Only track information and playlist number are displayed on the multifuction (instrument cluster) display. Steering wheel controls work just fine, and in the iPod User Interface mode, all of the iPod functions are available on the iPod (which is why I wanted it in the console, not in the glove compartment; further, the USB input is for music files on thumb drives, and is also the way firmware updates are made, so I wanted it there too). The COMAND CDC controls set normal play, repeat, mix, etc. for the iPod as it does for the CDC.

The lack of adequate documentation is the Achilles' heel of the GW 500. With the unit costing around $500, I feel more like a beta tester, when I should have gotten the gold standard for that cost. However, I expect the results will be worth it, once I learn the interface adequately. The improvement in sound quality over mp3 DVD and the integration with COMAND and steering wheel controls is great.

I hope this documentation and that to follow will help someone. For those who like diagrams, the before-and after MOST fiber optic rings for my '05 W220 are below. Check the phone bulletins on Paul's site for your car - thay are not all configured the same. The change in position of the VCS (Voice Control System) and CDC (CD Changer) in the diagrams is effected by swapping the fiber optic connections between the two. However, I believe that despite the switch, the MOST master controller still sees the CDC as component 4 and the VCS as component 2 on the STAR diagnostics menu, beccause no STAR diagnostics reprogramming is necessary for the installation. I just didn't change it in the diagram.

After the changes, all of the items on the ring - VCS, nav, radio, telephone, etc. worked as before, except that now the GW 500 would replace the CDC in the ring when desired.

I do want to thank Rob13572468 again for his time and patience; we had frequent private message correspondence putting our ideas together to resolve the problem. He is in Chicago, I am in Tampa - but some of his PM traffic is time stamped at 1:30 AM, so I know he worked late to help. His help was invaluable.

[GW500]

Hi Skylaw! Nice description! I wish that you will be a satisfied user, finally.

You are right, the documents have space for development , but imagine this is not only for Mercedes, but you get the same box and manuals for your Audi/BMW/Mini/Porsche/Saab etc.
Each brand has different models/HUs/options/setups, moreover these might change from MY to MY ... the Ideal Manual would be a VERY big book.

These units are built in by professional installers usually. They know the cars better than an AM manufacturing company. For them some words would be enough: "install it right before the CDC in the MOST ring".
After the first couple of ten installation, most of them could write a much better manual than the original one.

[Skylaw]

Originally Posted by GW500

Hi Skylaw! Nice description! I wish that you will be a satisfied user, finally.

You are right, the documents have space for development , but imagine this is not only for Mercedes, but you get the same box and manuals for your Audi/BMW/Mini/Porsche/Saab etc.
Each brand has different models/HUs/options/setups, moreover these might change from MY to MY ... the Ideal Manual would be a VERY big book.

These units are built in by professional installers usually. They know the cars better than an AM manufacturing company. For them some words would be enough: "install it right before the CDC in the MOST ring".
After the first couple of ten installation, most of them could write a much better manual than the original one.

Hi, GW500 - good to hear from you again. I agree that verbiage in the installation manual directing installation of the GW 500 unit immediately before the CDC in the MOST ring would be appropriate (and for those who aren't pros, perhaps a statement that "failure to do so will result in the GW 500 failing to replace the CDC in the MOST ring.") By the way, I am not a professional installer - I rate myself as only a "fair" shade tree mechanic on some systems - and not even that on many.

I also understand why the instructions for every kind of head unit could not be included. A bit later I will post photos of what I had to do in my trunk to accomplish proper placement in the ring - and my recommendation (for cars with trunk mounted CD changers) to leave it to a professional installer with Mercedes fiber optic experience, or at least to someone with prior experience working their fiber optic systems. It is a tough job for a beginner.

And, for COMAND owners, I'll post some hints on getting into the GW 500 menus successfully the first time - it isn't completely intuitive from the user manual. Hope to get there tonight or possibly tomorrow - right now I'm revising the photos posted earlier to make them easier to see.

[My04230k]

Skylaw,

Congrats on a successful install and your text an pics are worth a million bucks!!
Now that you have the gateway, I feel like I am the only guy dealing with the DVD-Audio.. but I gues a change is coming. I kinda wish I would have kept the GW500 I put in my Audi and tried to do a firmware change to get it to work on my benz but the Dates were just too far away for me to risk support.
Well, your locations are outstanding. Exactly what I had in mind, Forgive me if I copy.. it is truly a work of art..

Congrats.....

Oh BTW. The GW500 I installed in my Audi had a bad habit of forgetting where it was if I turned off the car for too long in shuffle mode. I would restart at the first song in my Ipod Library which happened to be a song I didn't care for much ( LOL ) and I had to manually put it back in shuffe. If you notice your GW500 does the same thing let me know please, I hope they fixed that. it was really irritating sometimes.

[GW500]

Originally Posted by My04230k

Oh BTW. The GW500 I installed in my Audi had a bad habit of forgetting where it was if I turned off the car for too long in shuffle mode. I would restart at the first song in my Ipod Library which happened to be a song I didn't care for much ( LOL ) and I had to manually put it back in shuffe. If you notice your GW500 does the same thing let me know please, I hope they fixed that. it was really irritating sometimes.

Source of the problem is that the Head Unit forces Shuffle OFF and/or Track 1 at startup. The GW should discard these commands.
It will be solved in v2.00, do you want to take part in a testing round?

[Skylaw]

Originally Posted by My04230k

Skylaw,
Well, your locations are outstanding. Exactly what I had in mind, Forgive me if I copy.. it is truly a work of art..

Thank you for your kind words, and please do copy.

I am going to grind the tabs on the USB clip a bit, because right now they interfere somewhat with the iPod connector below it. I will also likely enlarge the hole at the back of the false floor a bit (cutting out a notch) to allow the USB connector to slide back a bit. Last, I'll invert the USB clip so that it fits more to the right in the picture. Those steps should give easier access to the iPod connector. Positioning of the USB clip is limited a bit by the need not to puncture the AUX/mode selector on the other side (I used the supplied screw, but will change that to a small nut & bolt).

I use my iPod in the car, mostly - and remove it primarily for updates to firmware and music, so a small bit of inteference from the USB clip isn't a problem. The iPod location requires no clip - the 4th Gen iPod fits perfectly without one, and the "active" clip sold as an option would be too big for this fitment.