Interpreting 7 digits model number suffix of WD drives

[SOSdonnees]

Hello,

Who can point me to the right document or a way to interpret the 7 last digits of this drive :
WD20NPVT-00Z2TT0

It's a 2 TB WD Green 2,5'' 15mm SATA hard drive coming from a MyPassport Studio USB/Firewire external enclosure.

The first part "WD20NPVT" can be explained with this document :
Model Numbers - WD Internal Drives
Model Number format fro WD Branded Products

This document tells that the model suffix number (after the hyphen) is only for in-house use.

However, I read in this forum that it was important to match the two digits at the middle of the suffix. True ?
Can someone explain the meaning of "Z2" (and possibly also of "TT") ?

Thanks.

[labtech]

Z2T is what is known as family code.

[Doomer]

That information encodes internal model name and model version and can uniquely identify particular hardware build

[fzabkar]

I haven't seen WD's internal document, but here is an explanation in Russian:
http://www.acelab.ru/dep.pc/doc.pc3000d ... in-N-2.pdf

Here is Google's English translation:
http://translate.google.com/translate?h ... in-N-2.pdf

[SOSdonnees]

Thank you.

I wonder if the two last digits of the suffix, known as the "Customer configuration code" according to the document posted by fzabkar can not also be considered as the firmware version, or if you prefer, some kind of "Customer firmware code", as I own a

WD800JD 75MSA3
Firmware A3