IEC/EN 61000-4-6 specifies the design and performance of a range of coupling/decoupling networks (CDNs). Each CDN is specific to the type of cable and the intended signal carried on the cable. The CDN M series is used to inject the RF disturbance on the main line (supply). Teseq offers an extensive range of CDN M4 series for four line applications and vast number of configuration. The presented CDN M4 series have a maximum current of 16 A and operating frequency starts from 150 kHz to 230 MHz. Teseq CDN M4 series comply fully with the requirements of the standard and provide a simple, reliable and safe method of injecting RF energy into the equipment under test (EUT).