Index of cooperation

In telecommunication, the term index of cooperation (diametral index of cooperation, international index of cooperation) has the following meanings:

• In facsimile, the product of the total line length and the number of lines per unit length, divided by π.
• For rotating devices, the product of the drum diameter and the number of lines per unit length.

Source: from Federal Standard 1037C and from MIL-STD-188