ISNs are devices used in testing conducted emissions along data or communication lines, commonly RJ45, D-sub 25 Pin, and coaxial cables. Many of these devices also doulbe as conducted RF immunity testing Coupling Decoupling Networks (CDNs).
These monitoring devices are placed between the equipment under test (EUT) and auxiliary equipment (AE) or load which are necessary for the operation of the EUT. The ISN establishes the common-mode termination impedance for the EUT’s telecommunications port during measurement.