VOC stands for Verification of Compliance, one of the equipment authorization modes defined by the US Federal Communications Commission (FCC). It applies exclusively to electronic and electrical products without intentional radio frequency (RF) transmitting functions. This is the core standard to distinguish different FCC compliance paths.

1. Three Historical FCC Equipment Authorization Paths

·Verification (VOC): Mainly for audio and video consumer electronic products.

·DoC (Declaration of Conformity): Applied to PCs & peripherals, lamps and home appliance controllers. VOC and DoC had slight differences in applicable products and laboratory requirements, but neither required official FCC application nor FCC ID assignment (manufacturer self-declaration mode).

·Certification (FCC ID): For products with Bluetooth, Wi-Fi, cellular and other RF transmitting modules. This path requires review by a TCB (Telecommunication Certification Body) with the strictest procedures.

  2. Merger of VOC & DoC into SDoC (2017 Regulatory Update)

On November 2, 2017, FCC updated Part 2.906 and launched the SDoC (Supplier's Declaration of Conformity) program, merging the original VOC and DoC into a unified framework.

·Transition Period: November 2, 2017 – November 2, 2018. Old VOC/DoC reports remained valid during this period.

·Full Implementation: After November 2, 2018, VOC and DoC were officially phased out. All products previously covered by VOC/DoC now follow the SDoC rule.

Industry Terminology Note: "FCC VOC" has become a historical official name, but the industry still uses the term habitually. The current official name is FCC SDoC. Both refer to the same compliance mode in daily communication.

  3. Product Scope of FCC SDoC

Applicable products must meet two conditions: the product generates unintentional electromagnetic radiation during operation, and has no built-in intentional RF transmitting modules.

Typical SDoC Products

PC & peripherals (host, monitor, mouse, keyboard), household appliances (refrigerator, electric kettle, hair dryer, washing machine), audio & video devices (speakers, amplifiers, non-smart TV boxes, DVD players), LED lighting products, power tools, electronic toys and access control security equipment.

Common Classification Pitfalls

·Microwave Ovens: Classified as ISM (Industrial, Scientific and Medical) devices under FCC Part 18, not Part 15B SDoC. Microwaves utilize 2450MHz RF energy for heating, which is intentional RF energy usage. They follow independent test standards and compliance paths.

·Smart Devices with Hidden RF Modules: Smart speakers with built-in Wi-Fi, LED control panels with Bluetooth remote control and other devices with hidden wireless functions must apply for FCC ID instead of SDoC, regardless of their main functions. Judge compliance paths based on actual hardware configuration, not product names.

Most SDoC products comply with FCC Part 15B, governing unintentional radiating digital devices.

Class A vs Class B (FCC Part 15B)

·Class A: For commercial, industrial and business environments (servers, industrial control cabinets). Looser EMC limit values.

·Class B: For consumer products used in residential environments (most household electronics). Stricter conduction and radiation limits (about 10~13dB tighter than Class A).

Misclassification (declaring Class A for residential products) will lead to penalties during FCC spot checks.

  4. Core Test Items for SDoC

FCC SDoC tests focus on EMC (Electromagnetic Compatibility), evaluating electromagnetic interference emitted by products. Two major test items are required:

4.1 Conducted Emission

Test frequency range: 150kHz ~ 30MHz. Measure RF interference voltage on power lines via LISN (Line Impedance Stabilization Network).

·150kHz ~ 500kHz: Quasi-peak: 66dBμV ~ 56dBμV; Average: 56dBμV ~ 46dBμV

·500kHz ~ 5MHz: Quasi-peak: 56dBμV; Average: 46dBμV

·5MHz ~ 30MHz: Quasi-peak: 60dBμV; Average: 50dBμV

Class A limits are about 10~13dB looser across all frequency bands.

4.2 Radiated Emission

Test basic frequency range: 30MHz ~ 1GHz. Extended range rules:

·Main clock frequency > 108MHz: Test up to 2GHz

·Main clock frequency 500MHz ~ 1GHz: Test up to 5GHz

·Main clock frequency > 1GHz: Test up to 5 times the clock frequency

Class B Radiated Limits (3m test distance):

·30MHz ~ 88MHz: 100μV/m (40dBμV/m)

·88MHz ~ 216MHz: 150μV/m (43.5dBμV/m)

·216MHz ~ 960MHz: 200μV/m (46dBμV/m)

Class A uses a 10m test distance with about 10dB looser limits.

Radiated emission is the most common failure item. Typical causes include unreasonable PCB layout, insufficient power line filtering, poor shell shielding and antenna effect of connecting cables. Rectification may require PCB revision, magnetic ring addition, filter component replacement and grounding optimization.

Additional Tests for Part 18 ISM Devices

For microwaves, ultrasonic cleaners and industrial heating equipment under FCC Part 18: Additional tests for ISM frequency band compliance and out-of-band radiation leakage are required.

BlueAsia provides professional FCC SDoC compliance testing and certification services. We assist manufacturers to complete EMC tests and obtain valid SDoC documents for US market access. Contact our consultant: 13534225140 (Benson).