Wiring an old hotel for wireless Internet access can easily cost more than $1 million in construction and cabling costs, and that doesn't even factor in the lost revenue when rooms are unavailable due to the work. But some hotels have found a way around that problem using power line communications, or PLC, products, from TELKONET Inc. The company's technology, also known as "broadband over power line," is installed in the basement of a building and connects to its existing electrical system. To get wired broadband access, guests simply plug a modem into any electrical outlet. "It did not make...