DID Codes

DID codes are the numbers used by Sony's manufacturing company, Digital Audio Disc Corporation, to identify the master copies of CDs duplicated in their pressing plants. DADC has used a number of different DID code series over the years:

• DIDC - Classical recordings released on Sony-affiliated record labels.
• DIDP - Popular (i.e., non-classical) recordings released on Sony-affiliated record labels. This appears to have also been broken down into separate numeric series beginning with DIDP-20000, DIDP-50000, DIDP-70000, and DIDP-90000.
• DIDX - Recordings pressed by DADC by released on non-Sony-affiliated record labels.
• DIDY - Recordings pressed by the US division of DADC for the Columbia House Record Club.
• DIDZ - Recordings released on WEA Japan. (This code was only used from 1983 to 1985.)
• DISP - Promotional releases.

While many early releases listed the DID codes on the exterior packaging, the presence of a DID code on a release doesn't necessarily mean that copy of the release was actually pressed by DADC. As more CD pressing plants opened around the world, the record labels would often have other manufacturers press later runs of releases originally manufactured by DADC, but wouldn't necessarily remove the DADC mastering code from the CD's packaging. In some cases the DIDX codes also appear in the matrix codes of CDs manufactured by other companies.

The CSIG code that appears on some 3" CD singles may also be a DADC-assigned mastering ID, which would make it a close cousin of the DID codes.