Coupling Decoupling Networks (CDN) Types T2/4/8 and RJ11/45

For conducted immunity testing according to IEC/EN 61000-4-6

For coupling and decoupling disturbing signals to an unscreened cable with balanced lines, CDN type T shall be used.

Technical specification:
Type T2 / T4 T8 RJ11 / RJ45 (for 1GBit/s)
Frequency range (RF In) (10 kHz) 150 kHz – 80 MHz / 230 MHz
Power Rating (RF In) 6 W (continuous)
Maximum Input Voltage AC 100 V
Maximum Input Voltage DC 150 V
Current Rating (AE – EUT) Terminal block RJ45 jack RJ11 / RJ45 jack






Ordering information:
Type Description
T2 Terminal block 2 pole, 150 kHz – 230 MHz
T2-N Terminal block 2 pole, 10 kHz – 80 MHz (NAMUR)
T4 Terminal block 4 pole, 150 kHz – 230 MHz
T4-N Terminal block 2 pole, 10 kHz – 80 MHz (NAMUR)
T8 RJ45 jack 8-pole, 150 kHz – 230 MHz
RJ11 RJ11 jack, 150 kHz – 230 MHz
RJ45 RJ45 jack, 150 kHz – 230 MHz


CDNs are the preferred coupling and decoupling devices, for reasons of test reproducibility and protection of the auxiliary equipment (AE). CDNs shall be used for appropriate coupling of the disturbing signal to the various cables connected to the equipment under test (EUT) and for preventing applied test signals from affecting other devices, equipment and systems that are not under test.

Some selected CDNs meet the requirements of CISPR 15 and CISPR 22 for emission testing in the extended frequency range of 80 MHz to 300 MHz. Along with the common mode impedance a curve of the voltage division factor over the frequency range of up to 300 MHz is supplied with these CDNs. Currently the types CDN-AF2, CDN-T2, CDN-M2, CDN-M3 and CDN-M2+3 meet the requirements of CISPR 15 / CISPR 22.

In order to calibrate a CDN you require:
– specific calibration adapter
– mounting bracket
– 150 Ω to 50 Ω adapter
For the first CDN a mounting bracket and a 150 Ω to 50 Ω adapter need to be acquired. For each additional CDN only a specific calibration adapter needs to be acquired.


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