CISPR 35

CISPR 35:2016 specifies electromagnetic immunity requirements for multimedia equipment (MME) with a rated AC or DC supply voltage not exceeding 600 V. It covers equipment intended for residential, commercial, and professional use, including products previously addressed by CISPR 20 and CISPR 24.

The standard establishes immunity test methods, test levels, and performance criteria to assess equipment operation when exposed to electromagnetic disturbances. It uses a function-based approach, meaning that testing requirements depend on the functions performed by the equipment rather than its product category.

Equipment subject to specific immunity requirements under other CISPR standards, excluding CISPR 20 and CISPR 24, is outside its scope where those requirements apply.

For help planning the overall evaluation, explore our EMC testing services.

CISPR 35 applies to products such as desktop computers, laptops, servers, printers, scanners, multifunction office equipment, monitors, televisions, set-top boxes, audio amplifiers, speakers, video conferencing systems, network switches, routers, modems, telecommunications equipment, and entertainment lighting controllers.

It also covers equipment combining several multimedia functions, including smart TVs, interactive displays, and integrated audio-video systems. The applicable immunity tests depend on the product’s functions, interfaces, and power connections.

International: CISPR 35 is an international EMC immunity standard for multimedia equipment. It provides a common basis for evaluating equipment immunity and is used directly or through national and regional adoptions.

European Union: CISPR 35 is adopted in Europe as EN 55035:2017+A11:2020, a harmonised standard under the EMC Directive 2014/30/EU. It can be used to demonstrate conformity with applicable immunity requirements. Test reports can form part of the technical documentation supporting the EU Declaration of Conformity and CE marking.

United Kingdom: BS EN 55035 is used to support compliance with applicable EMC requirements under the UK Electromagnetic Compatibility Regulations 2016.

Australia and New Zealand: CISPR 35 is adopted as AS/NZS CISPR 35 and provides immunity requirements for multimedia equipment. However, immunity testing is not generally a mandatory requirement under the ACMA EMC regulatory framework.

United States and Canada: CISPR 35 is not generally required for FCC Part 15 or ICES-003 compliance, which primarily address electromagnetic emissions. Manufacturers may nevertheless use CISPR 35 for product qualification, customer specifications, or international market access.

Related Standards: CISPR 35 complements CISPR 32, which addresses electromagnetic emissions from multimedia equipment. Together, they provide emission and immunity requirements for this equipment category. Products with radio functions may also be subject to additional requirements under standards such as the EN 301 489 series.

CISPR 35:2016 covers several types of electromagnetic disturbances that can affect multimedia equipment during normal operation. The standard identifies which immunity tests apply to the equipment enclosure, power connections, and communication interfaces. Test selection depends on the product’s available ports, operating conditions, and primary functions.

Not every test is required for every product. CISPR 35 determines applicability through the relevant port requirements and the functions being assessed. Additional provisions apply to broadcast reception, printing, scanning, displays, audio output, networking, and telephony.

CISPR 35:2016 specifies immunity test levels for enclosure, AC mains, DC network power, and analogue/digital data ports. The applicable requirements depend on the equipment’s interfaces, intended installation, and operating functions. The following table summarizes the principal requirements from Tables 1 to 4 of the standard.

Important Test Conditions

Port applicability: Not every immunity test applies to every multimedia product. Conducted RF immunity, EFT, and surge requirements depend on the port type and applicable conditions. For analogue/digital data ports and DC network power ports, Tables 2 and 3 apply to ports supporting cable lengths greater than 3 m, according to the manufacturer’s specifications.

Surge on communication ports: Surge testing under Table 2 applies to qualifying ports that may connect directly to cables leaving the building structure. These must also be classified as antenna ports, wired network ports, or broadcast receiver tuner ports. Typical examples include xDSL, PSTN, CATV, and antenna connections. LAN ports and similar interfaces are excluded from these surge requirements.

RF test levels: The specified conducted and radiated RF levels are unmodulated values. Where the required level varies across a frequency range, interpolation is linear with the logarithm of frequency. At a transition between different test levels, the higher value applies.

Magnetic field immunity: Power-frequency magnetic field testing applies only to equipment containing components inherently sensitive to magnetic fields, such as CRT displays, Hall-effect elements, magnetic sensors, and certain audio components.

Additional requirements: Equipment with telephony, broadcast reception, audio, display, or networking functions may require additional test frequencies, specific operating conditions, or modified performance criteria under the relevant annexes of CISPR 35.

Reference: CISPR 35:2016, Clause 5, Tables 1 to 4, and applicable normative annexes.

Not Applicable

CISPR 35:2016 requires multimedia equipment to be tested in a configuration representative of its intended use. The equipment must be operating in a way that allows its primary functions to be monitored while electromagnetic disturbances are applied.

Test Configuration

The test arrangement depends on how the equipment is normally installed. Desktop products are generally tested on a table, floor-standing equipment on the floor, and rack-mounted equipment either in a rack or on a table, as permitted by the standard.

Where external equipment is needed to operate or monitor the product, a representative arrangement of associated equipment must be connected. At least one port of each type must be connected and exercised. When several ports or modules have similar immunity characteristics, a representative selection may be used, provided the configuration is documented.

Manufacturer-supplied cables must be used where provided. Otherwise, suitable cables must be selected according to the product specifications. Any required grounding arrangements, external protection devices, or special installation measures must also be included in the test setup.

Operating Modes and Functional Monitoring

The manufacturer must identify the equipment’s primary functions, operating modes, and applicable performance criteria before testing. These details form part of the test plan and must be recorded in the test report.

Where practical, several functions can be exercised during the same test. For example, a multifunction printer may receive data through its network connection while printing and displaying information. This allows multiple functions to be evaluated without repeating the entire immunity test.

Some functions can be assessed directly, such as observing a display or monitoring an audio output. Others require an indirect assessment. For example, data recorded during an immunity test may need to be played back afterward to check whether the recording was affected.

Performance Criteria

CISPR 35 uses three general performance criteria to determine whether the equipment responds acceptably to electromagnetic disturbances.

Function-Specific Requirements

The general criteria do not cover every aspect of multimedia equipment performance. CISPR 35 includes additional requirements for broadcast reception, printing, scanning, displays, musical tone generation, networking, audio output, and telephony in Annexes A through H.

These annexes take precedence over the general performance criteria when they apply. For example, display functions may require assessment of image quality, while networking functions may require monitoring of data transmission or connection performance.

A product with several primary functions must satisfy the relevant requirements for each function. A failure of any applicable primary function to meet its performance criteria means the equipment does not comply with CISPR 35.

When Is Surge Testing Required on I/O Ports?

One important consideration when preparing a CISPR 35 immunity test plan is determining whether surge testing applies to the equipment’s communication and I/O interfaces. Unlike AC mains power ports, not every signal or data connection is subject to surge testing.

Under CISPR 35:2016, Table 2, surge testing applies to analogue/digital data ports only when both of the following conditions are satisfied:

• The port may connect directly to cables that leave the building structure.
• The port is classified as an antenna port, wired network port, or broadcast receiver tuner port under the definitions of CISPR 35.

The standard identifies xDSL, PSTN, CATV, antenna, and similar connections as typical examples. LAN ports and similar interfaces are excluded from the surge requirements of Table 2.

This distinction is particularly important for equipment with several communication interfaces. A product may include Ethernet, USB, coaxial, and telephone connections, but these interfaces do not necessarily have the same surge immunity requirements.

Surge Test Levels for Applicable I/O Ports

Where primary surge protection is part of the intended installation, testing is performed with that protection fitted. The actual protection device should be used where possible. CISPR 35 also permits an alternative surge waveform and appropriate coupling network where the specified 10/700 µs coupling arrangement interferes with the operation of high-speed data ports.

Does Cable Length Affect Surge Applicability?

Yes, but cable length must not be considered in isolation. Table 2 applies to ports specified by the manufacturer to support cables longer than 3 m. For surge testing, the additional conditions concerning cables leaving the building and the port classification must also be satisfied.

For DC network power ports, Table 3 specifies a separate surge requirement of 0.5 kV, line-to-reference ground, where the manufacturer’s specification permits direct connection to outdoor cables. The Table 3 requirements also apply only to ports supporting cable lengths greater than 3 m.

Practical Recommendations Before Testing

Manufacturers should review the intended installation and cable connections before finalizing the immunity test plan. In particular, it is useful to establish whether communication cables remain within the building, whether any interface is intended for direct outdoor connection, and whether external surge protection is required by the installation instructions.

These details should be consistent with the product documentation. Identifying the applicable ports early can prevent unnecessary testing and help ensure that surge protection is evaluated under the correct installation conditions.

Reference: CISPR 35:2016, Table 2, Clause 2.4 and associated notes; Table 3, Clause 3.2; and Clause 5.

Use EMC pre-compliance testing to investigate immunity weaknesses and refine functional monitoring before formal evaluation.