Newbie question re: DVD rear screen for COMAND in W211 2003.

[dsolds]

Hi all, first post for me here; looks like a well informed forum.

I have looked and searched through for information on this subject without success so I guess I'll ask.
I have a 2003 E500 Estate with COMAND and I would like to have a headrest screen fitted so the lad can watch DVD's in the back. From the research I have done it seems there is a 25 way D type connector on the back of the COMAND unit for this very purpose which MB use for their (expensive and flimsy) centre console mounted offering.
Assuming this connector is what it purports to be, does anyone have a pin-out configuration for it please? I am quite happy to modify a headrest mounted unit to have this plug on but I cannot find the pin config anywhere.
Tried using the "liberation" code enabling the DVD to play on the move. Don't care what anyone says, this is very distracting so I set it back to turn off when the car is moving, hence my desire to have a headrest mounted screen.
Thanks in advance.
Dom.

[richard]

Not all W211 COMANDs have that connector. They stopped putting it on by default at some point along with the video input (green fakra coax connector) - as yours is 2003 it probably does have it though..

R

[edit, the A/B class comand lost that input around 2007 also)

[migabc]

Hi all, first post for me here; looks like a well informed forum.

I have looked and searched through for information on this subject without success so I guess I'll ask.
I have a 2003 E500 Estate with COMAND and I would like to have a headrest screen fitted so the lad can watch DVD's in the back. From the research I have done it seems there is a 25 way D type connector on the back of the COMAND unit for this very purpose which MB use for their (expensive and flimsy) centre console mounted offering.
Assuming this connector is what it purports to be, does anyone have a pin-out configuration for it please? I am quite happy to modify a headrest mounted unit to have this plug on but I cannot find the pin config anywhere.
Tried using the "liberation" code enabling the DVD to play on the move. Don't care what anyone says, this is very distracting so I set it back to turn off when the car is moving, hence my desire to have a headrest mounted screen.
Thanks in advance.
Dom.

Here's the pin out.

Rear connectors:
The W211 EURO spec COMAND APS unit (Model No.: 6061) has 4 connectors on the back:
1 - Green FAKRA - Video Input (only if Video capable)
2 - 25-way D-Type - Rear Screen (only if Video capable)
3 - 3 Way - AUX audio input
4 - Multiway - Power, Ground, Wakeup & MOST fibre plug

Here's the Pin-out for the D25 (Rear Screen) connector:
1 Ubat+ (circuit 30)
3 AUDIO R
4 AUDIO L
6 CAN Low
7 CAN High
8 CVBS (FBAS)
14 Circuit 31
15 AUDIO screening
16 AUDIO ground
20 AUDIO GND CYBS (FBAS) ground
** All other pins are not assigned

[richard]

Here's the pin out.

Rear connectors:
The W211 EURO spec COMAND APS unit (Model No.: 6061) has 4 connectors on the back:
1 - Green FAKRA - Video Input (only if Video capable)
2 - 25-way D-Type - Rear Screen (only if Video capable)
3 - 3 Way - AUX audio input
4 - Multiway - Power, Ground, Wakeup & MOST fibre plug

Here's the Pin-out for the D25 (Rear Screen) connector:
1 Ubat+ (circuit 30)
3 AUDIO R
4 AUDIO L
6 CAN Low
7 CAN High
8 CVBS (FBAS)
14 Circuit 31
15 AUDIO screening
16 AUDIO ground
20 AUDIO GND CYBS (FBAS) ground
** All other pins are not assigned

The "worrying" thing about the above pin out is the 'CANbus' - it is quite possible the comand will not output anything until it has talked to the electronics in the Mercedes monitor over the Canbus.
So you may have to start with a Mercedes monitor and mount that in a headrest

R

[dsolds]

Wow. So much quality info in such a short space of time. Thanks loads for this Gents, it is much appreciated.
Since I already have a screen with some speakers fitted (came from a portable set) I will try this over the course of the next week or so, work permitting, and post the initial results.
The downside with the Merc monitor is its size. It is too large to be able to carve it into the headrest. The Merc centre console mount idea......hmmmm. Kids and feet come to mind.
Wouldn't bother except we travel to see my brother every fortnight from Tamworth to Maidstone and back which is a long journey for 2 and 3 year olds.
Thanks again. Dom

[barneybeardsall]

Hi,
Looking forward to hearing your outcome on this... as I too am looking for s simular solution for my 4 year old...

[dsolds]

Righto, the first set of results. Not too encouraging I'm afraid.
Firstly I am still reading up on exactly what this CAN bus thingy is all about. But I suspect it has something to do with why this thing won't work. Using an oscilloscope to check the audio outputs first of all reveals that these pins (3 and 4) are dead under all circumstances. This leads me to believe that the machine is waiting to "see" a screen connected before it livens up the outputs. :mad:
So, tentatively connected up the monitor's video input half expecting some (expensive) smoke to appear. Nothing. With a capital "F" :devil:
Have scoped all pins on the connector with almost zero results except on pins 6 and 7 which lends credence to Richard's theory that the CAN bus is trying to "poll" the bus to check for the presence of the MB rear screen before livening up the outputs. Unless of course it has to go on the STAR machine to "tell it" that the rear screen is actually fitted.
Now, if this is correct, there are 2 issues. I either have to try and butcher some electronics from a MB screen since the genuine item is too large to carve into an E class headrest, or I fit an aftermarket DVD player in the glovebox with some cordless headphones. The upside to this option is that the kids can sit in their headphones and I can enjoy classic FM at the same time.
A third option which I have yet to check for feasability is to try an aftermarket DVD player connecting the video output to an aftermarket screen but with the audio plumbed in to the AUX input on the COMAND.
Jeez I hate overly complex stuff.
Come the revolution.......

All suggestions, rude or otherwise, gratefully accepted. Not that I'm getting desperate you understand. :confused:

[dsolds]

OK, I've officially given up on this idea now. The CANBUS seems like it's connected to just about everything in the car including the damn fag lighter.
MB aren't being overly helpful either though to be fair I doubt anyone outside the MB factory really knows what the electronics are doing in great depth.
It seems that all items on the CANBUS have to have an electronic address of some sort which identifies it to the main processor. No knowing how to reproduce this address and not knowing which addresses are "free" is preventing me from going too much further.
Also, not wanting to pay MB prices for the genuine article so I can analyse the CANBUS whilst operating the screen is a major dead end as well.
From what I can remember of trying the Dension IPOD interface in my last W211 even having the right information is no guarantee of success 'cos that thing never worked properly. Kept disabling the 6 stack CD in the dash so I got rid of it in the end.
No, despite a HND in electronic engineering this one is the one that got away. I bow to the greater power that is MB design labs. :(
So, if anyone comes across a solution to this I would be very interested indeed - read "lots of beer" interested.