Computer company Cisco Systems advised the Federal Communications Commission that it should postpone allowing unlicensed mobile devices to operate in the digital-TV-spectrum band until it can be assured that there will be no harmful interference to DTV reception.
"Harmful interference, even if intermittent, should not be permitted to degrade existing operations in the band or the consumer's experience in watching video programming," Cisco wrote in comments to the FCC.
Broadcasters have argued the same thing, although they are less confident than FCC chairman Kevin Martin and others that there can ever be assurance that the devices, which seek out unused frequencies (so-called white spaces) to transmit on, can effectively seek those vacant channels without putting DTV reception at risk.
FCC testing of TVs and the devices -- personal digital assistants, laptops -- found interference problems, but the agency is retesting at the behest of equipment manufacturers.
In addition, Cisco wrote, the commission should not approve the devices if they will interfere with cable set-top boxes, which operate on channels 3 and 4.
"We encourage the commission and its engineering staff to take time to assure themselves that the relevant technical issues have been identified prior to writing rules for the use of white spaces and for certification of devices that will be deployed there," Cisco said. "The commission should not hesitate to postpone its planned October action on final rules to the extent that staff need some additional time to address the complex engineering questions presented by this docket."
That October date is not set in stone, with Martin saying that it will depend on when FCC engineers have completed their evaluations.