How to Keep Your Digital Signage From Being Shut Down by the FCC
By Darrin Friskney
May 19, 2017
Recently, a fried chicken restaurant franchise in Texas was forced to turn off its imported outdoor LED signs at two locations because they were emitting so much radio interference that the FCC cited them for threatening the safety of airport communications miles away.
Digital billboards and LED signs also are increasingly being blamed for wreaking havoc with uplink signals to nearby cell towers. Recently, digital billboards in Tennessee, Oklahoma and New Jersey have had problems with emitting interference.
Complaints of this nature are on the rise in part due to growing reliance on the more sensitive 4G wireless technology, and most complaints seemingly are arising from the increased use of Asian-manufactured LED display products, which often are not FCC compliant.
The reason for this is that most Asian-manufactured LED signs and digital billboards have a common design flaw which produces high emissions and cannot be easily fixed. Specifically, the most common Asian sign architecture uses an intermediate controller unit called a "receiver card" that sits between the controller and the sign's LED panels or "modules." In this type of architecture, which is proliferating because it is cheap to manufacture, the modules are passive so they rely on data delivered from the receiver card over multi-conductor cables in order to display an image.
To correctly display the image using this architecture, the data must be transmitted at very high speeds, upwards of 30 MHz. Digital signals that operate this fast make multiples of themselves, which creates what are known as harmonics, or potentially harmful emissions at multiple frequencies.
Asian products with receiver cards distribute the data and clocks to the modules via a host of cables and connections, compounding the harmful emissions. Even if the cables are shielded, which often is not the case, they still emit too much electromagnetic noise to satisfy FCC guidelines.
Are FCC rules being disregarded?
The FCC requires that electronic equipment, such as digital signs, be tested in a worst-case scenario to ensure compliance with emissions limits, and to show that the equipment won't cause harmful electromagnetic interference to other devices. The specific section of FCC code that governs digital signs resides in Part 15 of Title 47.
However, the FCC does not actually perform this testing. Instead, an honor-system requires that the manufacturer receives verification of the final product from an accredited third-party testing lab. There is no database or registry to document which products have been tested. Once the product has been verified, Part 15 requires that a sticker, sometimes referred to as a "two-part warning," be affixed to the exterior of the product.
Despite these regulations, many importers either don't have their digital signs tested, or their signs fail and the manufacturers continue to sell these products in the United States to unsuspecting buyers. Perhaps for this reason, many Asian imports are missing the required Part 15 verification sticker, a tell-tale indicator that verification has been omitted. In addition, independent testing of Asian-manufactured signs has confirmed that the tested products dramatically failed to meet the FCC's interference limits across the board.
Even more concerning is evidence that some importers are temporarily altering their LED signs to pass testing, and then changing them back for shipping and installation. Since high speed data is a major contributor to emission noise, these manufacturers eliminate data transfer from the controller by removing or disabling it during testing.
Because the FCC has implemented a "self-directed" testing program, the environment is ripe for importers to either skirt the system or to outright cheat. Perhaps their disregard for the law stems from the perception that their violations will go undetected.
Unfortunately, businesses owners who are buying these products often don't know enough to verify that a product is compliant with the FCC's rules. They trust in the system, and the manufacturer. All too often they first learn about the problem when they receive a cease and desist letter, either from the FCC or from one of the cellular companies.
The entire signage industry is at risk
Sign owners with a non-compliant sign are faced with shutting off the sign and paying a hefty fine. This can cost sign owners tens of thousands of dollars. The impact is particularly devastating for small business owners, who buy the majority of LED signs sold. Not only is their large investment in a digital sign rendered worthless, their main advertising vehicle also is taken away.
Once the FCC is involved, the manufacturers that sell equipment without the appropriate verification can be fined, but that's little comfort to a small business owner trying to keep the doors open.
In addition to the disastrous repercussions a sign owner might face, sign companies can be harmed as well, as they most likely will bear some of the cost to replace the offending signs. Certainly, their reputations will take a blow.
This contempt for American law can also have far reaching implications in the U.S economy. North American manufacturers, who have a history of following guidelines, face unfair competition from foreign manufacturers who are cutting corners to offer cheaper products.
How to avoid being a victim
There are several steps that sign operators and dealers can take to ensure the digital sign they are buying or specifying meets FCC Part 15 emissions guidelines. Here are some questions to ask the sign manufacturer:
- What specific FCC rules govern your product, and how specifically have you complied with those rules?
- Do you fall under any exemptions as outlined in Title 47 Part 15.103?
- Can you provide the test report that shows that this exact model meets the requirements of Title 47 Sections 2.955, 15.105, 15.107 and 15.109?
- Was the equipment tested under normal operating conditions and in a state such as to cause maximum emissions as prescribed by FCC Part 15?
- Can you provide a photo of the label that meets the requirements of Title 47 Part 15.19?
Reputable manufacturers will be happy to provide the information and education needed to ensure their digital sign product meets all FCC standards.