The Federal Communications Commission (FCC) recently issued a Notification of Harmful Interference against a Brooklyn resident, alleging that he operated a bitcoin miner in a manner that caused spurious emissions on the 700 MHz band, which interfered with T-Mobile’s LTE network. The FCC warned the purported offender that continued operation of the bitcoin miner that causes interference could result in his being subject to steep fines, equipment confiscation and even prison time. As part of its ongoing enforcement action, the FCC ordered the suspect to respond to a series of questions about the bitcoin minder, including his use of the device, the make and model number, FCC labeling compliance, and identification of the vendor that sold it to him.
FCC Continues Strict Enforcement of Its RF Equipment Rules
This case is a powerful example of the FCC’s continuing trend of cracking down on violators of its radio frequency (RF) equipment rules. This episode is somewhat unusual, because the FCC typically targets manufacturers, importers or vendors marketing unauthorized or improperly labeled RF devices. In this instance, the FCC is not (at least at this stage of the investigation) concerned with noncompliant equipment. Rather, the Commission us targeting the use of an apparently compliant RF device that resulted in harmful interference. The FCC hinted that the subject device may have been improperly modified in a manner that resulted in operation on an unauthorized frequency.
FCC’s Interest in Bitcoin Miners
Bitcoin miners add transaction records to bitcoin’s blockchain. The bitcoin protocol stipulates that 21 million bitcoins will exist at some point. What miners do is bring them out into the light, a few at a time. The miners’ operators are permitted to do this a reward for creating blocks of validated transactions and including them in the blockchain. Bitcoin mining is accomplished by a series of nodes that run bitcoin software and keep bitcoin going by participating in the relay of information—i.e., spreading btransactions around the blockchain.
At first blush, bitcoin miners may appear to be a curious target for FCC enforcement, as they do not seem to fit into the categories of devices that clearly have the potential of causing harmful interference. In the past, the FCC has commenced actions against suppliers that marketed equipment such as Wi-Fi routers, smart meters, jammers, digital signage, RFID readers, and radio transmitters that caused interference or were otherwise not in compliance with its rules.
At issue in this case is the bitcoin miner’s circuit-based RF hardware. Older miners have central processing units (CPUs); more recent models use graphics processing units (GPUs), field programming gate arrays (FPGAs) or application-specific integrated circuits (ASICs). The miner at issue uses ASIC.
These types of hardware are classified by the FCC as “unintentional radiators,” i.e., devices that use digital logic, electrical signals operating at radio frequencies for use within the product, or send radio frequency signals by conduction to associated equipment, but do not transmit RF energy. The FCC regulates unintentional regulators by requiring the responsible party (typically the manufacturer or importer) to conduct testing and self-authorize its device by preparing a Supplier’s Declaration of Conformity, attesting that the device complies with the FCC’s emissions limits and other technical rules before it is marketed in the United States.
Consequently, bitcoin miners are subject to the same FCC rules as PCs, peripherals, sensors, and other types of unintentional radiators.