KEH-M9741ZT is this a ip-bus compatible head unit

[crazyls]

I originally posted this as pioneer p626 but I got no response, so I figured that was not the correct designation its a pioneer KEH-M9741ZT.  its a 1992 ls 400 and nobody make a aftermarket changer for it.
thanks
tr

[andrethomas]

Care to take a photo of the back?

[crazyls]

hey thanks for the response, since the things inplace in the car I'll have to have somebody else that's pulled one take a photo. this may take awhile!
thanks
tr

[crazyls]

quick thought,  would a picture of the changer side (connector) of the equation help? Because thats much easier to do!
thanks
tr

[andrethomas]

Have a look at the image on the site (http://www.vitat.spb.ru/eng/index.php?L1=ip-bus)

There is a picture of the IPBUS pinout. The connecter on your headunit should resemble that image. It may also be that the connector on the cd changer will look the same.

If so, it is very possible that it may be IPBUS compatible.

The Model number on your post definately looks like a pioneer model number... so it is pioneer... the question is just - is it ipbus compatible?

[crazyls]

thanks, I'll yank the changer tonight!  theres a big desire amongst the early lexus ls 400 owners in resolving this issue so maybe I'll get somewhere.  Heck even if I have to scope it I will!
once again thanks
tr

[crazyls]

heres a link to what I think is the back of the hu with wiring diagrams

http://www.cureline.net/lex/audio/howto_wiring_daigrams.htm

thanks again

[andrethomas]

It doesnt look good at all.....

I suspect it is not IPBUS after all - The control protocols will probably be hidden in TXM+/TXM- and TXS+/TXS-

In all probability, being older of breed, it may be that it will contain 5volt logic which will be rather easy to see what is going on.

What do you intend doing?

[andrethomas]

Just a quick thought - Its probably differential BUS (Similar to CAN or IPBUS, which is actually rebranded IEBUS) - You will find they used two busses - One for communication from headunit to cd changer and one for communication from cd changer to head unit.

If you take into consideration that BUS communication usually involves MASTERS and SLAVES I would suspect that TXM+/TXM- would be the Transmit (TX) from the MASTER (being your head unit) - also meaning communication going from the head unit to the cd changer

AND

TXS+/TXS- would be Transmit (TX) from the SLAVE (being the cd changer) inplying that the bus is used for communication from the CD CHANGER (Slave) to the Head unit (Master)

I am just guessing.....

[crazyls]

yea I just started looking at the wd's,  like you said if its just signaling 5v this should be easy.  What I intend to to and what I actually do are probably quite different, times the limiting factor I have two young kids...  I'll throw my friends logic analyzer at it and see what happens if its just 5v signals I either pic it or mini-itx it.  I've gone with the mini-itx before its more expensive but I can do more things quickly!

thanks for you input on this!