DEC 7 | Asymmetrical Line Decoupling

DEC 7 - 6.6 kV Decoupling Network for Asymmetrical Lines

20 mH inductors, not current-compensated for asymmetrical signal-line testing.

The Haefely DEC 7 separates auxiliary equipment from an EUT during transient immunity testing on unshielded asymmetrical lines. It supports up to four wires and impulses up to 6.6 kV, using 20 mh inductors, not current-compensated. Coupling is performed by a separate network, allowing protection and decoupling to match the signal circuit.

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HAEFELY EMC

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TEST STANDARDS:

IEC/EN 61000-4-12 ,
IEC/EN 61000-4-5 ,

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DEC 7 Datasheet V2026.06

SPECIFICATIONS

HAEFELY EMC ACCESSORIES

DEC 7 - 6.6 kV Decoupling Network for Asymmetrical Lines

20 mH inductors, not current-compensated for asymmetrical signal-line testing.

Overview and application

Manual protection selection makes the connected protection elements visible.
The decoupling network does not generate or couple the test impulse; use it with a suitable coupling network and generator.
Select EUT voltage, current and signal bandwidth together; the decoupling path can affect normal communication.
Manufacturer-listed coupling networks: PCD 126A and IP6.2. Other decoupling elements are available on request.

The two EUT voltage ratings are reproduced without assigning them to varistors or ABDs; the datasheet does not identify that mapping.

Technical specifications

Specification	Details
Function	Decoupling and auxiliary-equipment protection; coupling supplied separately
Line type / capacity	Unshielded asymmetrical data and control lines; up to 4 wires
Supported impulse shapes	1.2/50 us - 8/20 us combination wave; 100 kHz ring wave
Maximum impulse amplitude	6.6 kV peak
Decoupling elements	20 mH inductors, not current-compensated
Protection elements	Varistors and avalanche breakdown diodes (ABDs)
Protection selection	Manual; operation without protection elements is also possible
EUT voltage ratings listed	Maximum 375 V DC / 265 V AC RMS, and 72 V DC / 50 V AC RMS. The datasheet does not map these limits to individual protection selections; confirm the intended configuration.
Maximum EUT line current	1.5 A
EUT signal bandwidth	Up to some 100 Hz
Connections	Safety banana sockets
Dimensions (W x D x H)	300 x 160 x 200 mm (11.8 x 6.3 x 7.9 in)
Weight	Approximately 6 kg net (13.2 lb)

Included components

DEC 7 decoupling network
Cable set
Four short-circuit bridges
User manual

Generator, EUT, auxiliary equipment and other coupling/decoupling networks are separate system equipment unless explicitly included above.

Standards and system configuration

IEC/EN 61000-4-5 Edition 2 Figures 11-13; Edition 3 Figure 9.
IEC/EN 61000-4-12 Edition 2 Figures 9-11; Edition 3 Figure 8.

Compare data-line coupling and decoupling networks

Product	Function	Signal circuit	Test waveform	Key ratings
PCD 121	Coupling	Symmetrical; 2 pairs / 4 wires	Combination wave	6.6 kV; selectable gas arrestor / ABD coupling
PCD 126A	Coupling	4 wires; asymmetrical surge; symmetrical or asymmetrical ring wave	Combination wave; 100 kHz ring wave	6.6 kV; capacitors, ABDs, gas arrestors or direct
DEC 5	Decoupling	Symmetrical; 4 wires	Combination, telecom and ring wave	6.6 kV; 20 mH compensated; 1 A
DEC 6	Decoupling	Symmetrical; 4 wires	Combination, telecom and ring wave	6.6 kV; 200 ohm; 0.1 A
DEC 7	Decoupling	Asymmetrical; 4 wires	Combination and ring wave	6.6 kV; 20 mH uncompensated; 1.5 A
PCD-1000-4	Coupling + decoupling	Balanced Ethernet; 1 / 2 / 4 pairs; 1000Base-T	Combination wave	4 kV / 150 A surge; 65 V DC / 1 A line; IEEE 802.3af PoE

Combination wave: 1.2/50 us voltage and 8/20 us current. Telecom wave: 10/700 us voltage and 5/320 us current. Ratings depend on the selected coupling/protection elements; review each product specification before configuring the system.

PCD 121 and PCD 126A provide coupling only. DEC 5, DEC 6 and DEC 7 provide decoupling/protection only. PCD-1000-4 combines both functions for high-speed Ethernet. IP4B is an EFT/burst clamp and is intentionally excluded from this matrix.