RCN appears to have found a way around both the infrastructure and building interference problems.
If the two do co-exist, though, engineers must learn to solve interference problems.
The field could become balkanized, creating both compatibility and signal interference problems for users.
A line code known as TC-PAM has none of the interference problems and three times the data throughput.
While computer and Internet companies like Google, Microsoft and Dell favored the idea, television broadcasters worried about possible interference problems.
There are, however, no interference problems with field-emission X-ray sources, so these can be used to take high-resolution pictures while treatment is proceeding.
PCM minimizes transmission losses and eliminates noise and interference problems because the receiving unit need only detect and identify simple pulse patterns.
"Wireless may be good if you're indoors and only within 20 or 30 feet," Mr. Altunian said, "but if you're talking 50, 75, 100 feet, you might run into interference problems and a weak signal".
Wi-Fi 5, which is just beginning to appear in PC cards and wireless base stations, eliminates some interference problems by operating on 5 gigahertz, a less crowded band of the spectrum.
Apart from causing interference problems, the "2B1Q" algorithm used to send broadband digital signals down a pair of copper telephone wires cannot punch its way through the "bridge taps" where local lines are spliced.
Julius Genachowski, the F.C.C. chairman, said he was confident that the commission's engineers would be able to work with the affected government and private entities to solve interference problems.
