ADLINK USB-7250 - Manual (Page 39)

Operations 29
USB-7230/7250
Figure 3-3: USB-7230 Isolated Input
Figure 3-4: USB-7250 Isolated Input
3.2 Change of State (COS) Detection
COS (Change of State) refers to input state (logic level) changing
from low to high or vice versa, wherein the COS detection circuit
registers the edge of the level change.