Most of those are M-codes.  Basically, the options that came on the vehicle.

For instance:

341 = Power Door Locks
425 = Rear Window Washer
553 = All the USA lighting and safety stuff

Etc.

You can find most of them here:

http://www.syncro.com.au/VW-T3-T25-Syncros-M-Codes

Cheers,

Jeff

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
JordanVw@AOL.COM
Sent: Tuesday, September 04, 2012 9:26 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Data tag - anyone fluent in these?

In a message dated 9/4/2012 3:45:51 A.M. Eastern Daylight Time,
dbeierl@ATTGLOBAL.NET writes:

Dear  Volks,

Here's the data tag from my '89 White Star.  Anyone care to  take a stab at
deciphering it?  I've made the images full size so you  can open them in a
new browser window and make them huge if it  helps reading the numbers.

_https://picasaweb.google.com/117189706757545167023/Vanagon89WhiteStarDataTa
g?authuser=0&authkey=Gv1sRgCLiE7syBtP2ytwE&feat=directlink_
(https://picasaweb.google.com/117189706757545167023/Vanagon89WhiteStarDataTa
g?authuser=0&aut
hkey=Gv1sRgCLiE7syBtP2ytwE&feat=directlink)

well the 25 in the Modell  column refers to T25...but im sure you  already
knew that LOL  the rest is greek to me..