Industry Standard Coding Identification
Industry Standard Coding Identification (ISCI) was a standard created to identify commercials that aired on TV in the United States, for ad agencies and advertisers from 1970 until 2004 (it was replaced by Ad-ID in 2005).
ISCI was invented in 1970 by David W. Dole with the backing of the American Association of Advertising Agencies (4As), the Association of National Advertisers (ANA), the National Association of Broadcasters (NAB), the SRA and the Television Bureau of Advertising (TVB) and it was maintained and operated by Dole until 1992, when the 4As and the ANA bought ISCI from Dole. In 2005, it was replaced by Ad-ID. 
An ISCI code was a set of 8 characters, the first four being alphabetic, and the remaining four being numeric, in the format 'ABCD1234' . The alphabetical characters usually represented the advertiser (some examples are QWAN for Wells Fargo Bank, KOCL for Coca-Cola, and PEMX for Pepsi), and the numeric characters were determined by the individual creating the code, with different numbers used for either different spots, or different versions of the same spot.
For example, a :30 second spot might have had a code of XECA1263, while the same commercial in a shortened :20 or :15 version (or in a different language such as Spanish) might have had a slightly different code of XECA1264. The ISCI code was unique to each individual commercial. The slightest change to an ad led to the use of another code.
ISCIs were printed on tape labels, in the production slate preceding the commercial on the tape or on digitally transmitted files through media distributors like DG, Vyvx, FastChannel and MediaDVX.
ISCI was replaced by Ad-ID in 2005. Ad-ID is the industry standard for identifying advertiser assets across all media platforms. Ad-IDs are 12 characters, except for SD spots, which are 11 characters. Ad-ID greatly improves workflow between agency, advertiser, media and their associated vendors, and removes the need for excessive human intervention and mistakes.