Prism
Operation Manual Issue 2.00
Page A.10
SCMS depends on the use of specially equipped recording machines which examine
these bits on the incoming digital audio interface and act accordingly. For example,
DAT recorders record two bits known as ID6 onto the recording medium according to
the SCMS information passed from the source. These bits control the SCMS Channel
Status transmitted when the tape is played back and control the further recording of the
audio data on other SCMS machines. If the recorder recognises that the material has
ID6 set to indicate that copyright exists and the material is not original, then a digital
copy is prohibited. However the 'rules' for converting the Copy Prohibit bit and Category
Code to recorded ID6 bits are rather complicated and this has led to confusion in the
professional industry, especially when SCMS and pre-SCMS equipment are connected
together.