[Galaxy Tab 2 Q&A, Help & Troubleshooting] Tech_Less:
CSC explained, such as it is, incuding what XAR and XAC mean

Stock OTA update or roms (generally speaking) has to match your specific csc on your devices stock firmware build.

The three letters after the model number signifies: 4 meanings, all valid indicating very different things. The hard part is deciphering what your CSC means and how that effects primarily your ability to upgrade correct software, whats bundled in it and maybe a hint why your not getting a OTA update.

1) the country or region(s) a model was bundled for (often csc for a tablet identity) XAC Canada, XAR Cellular south of USA

2) The carrier product code is firmware bundeled by every cell provider . Each has thier own and a different csc code even when a parent company is servicing a different country or region(s) within a country, Think Virgin Mobile in Europe, UK, USA etc... .

3) The consumer specification code . These are either bundle software by options.. of say Samsung G3 vrs Samsung G3 lite, or Italian vrs English, or Both.... consumer type, app and use options... basically limitations or exceptions between software bundles for same basic model depending on where its being sold. You know, bells, whistles, cultures, even age, sex and race user groups can require important distinct features between standard stock builds multiplied by makes and models. Targeted software, use, design..

4) The customer product code. So you bought a device off web, on sale, not affiliated with any carrier, specific country or region, bulk generic bundles. Eg. travelling abroad with your tablet bought generically over here or buying a GS5 in Tokyo airport on your way home to USA.

Why is that a problem? Depends where you physically are, with a device from? With certain customisations or exceptions and how does OTA connect via unfamiliar local data access but foriegn from the csc perspective. USA CARRIER but Japenese csc...

I suck at explaining but read article I reference down below.... Burners are probably in this work around .

Be certain the build+model+csc is same before choosing a flash rom or upgrading your stock firmware. Odin, Kies etc will likely refuse to flash/sync/upgrade if there is a mismatch in csc more often than any other reason

Here is a helpful, current and informative blog by Wilma Dee that explains csc much better, some great work arounds, csc troubleshooting and major carrier code plus country code lists,

Since I'm new here, I dont know her, I wont post a link but I really feel this paper is worthy of XDA scrutiny and appreciation. Search Google with this title, posted April 15 2014.

How To Change the CSC Code on Samsung Galaxy S5

These are not complete lists, they are Samsung specific, GS5 specific. as she lists them and its alot.

Are the country codes at least unified between all brands? I dont know but not likely.

There are different brands, with differently configured tabs and cells, in different countries and several distinct regions within each country, many data carriers with subsiduary carrier companies in diferent countries, regions, languages, configurations etc etc etc.

No wonder answering what does CSC stands for, means for your device, lists of codes is so hard to do .