The intent of this procedure is to determine the crosstalk ratios between any two optical paths in a cable, connectorized cable, splice or similar device. In addition, the device's contribution to the crosstalk in a system may be determined. The effectiveness of the material surrounding the optical conducting device in restricting light paths to other elements may also be measured. However, note that the test methods of FOTP-180 should be used to measure crosstalk in fiber optic couplers (branching devices) and in similar devices of this class.