28-01-2012, 02:40 PM
BROADBAND OVER POWER LINES (BPL)
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INTRODUCTION
Power line communications (PLC), or Broadband over Power Line (BPL) -- the practice goes by either name -- uses an RF signal sent over medium- and low-voltage AC power lines to allow end users to connect to the internet. The RF signal is modulated with digital information that is converted by an interface in the home or small business into Ethernet-compatible data.
By "medium- and low voltage," the power companies mean the residential power lines that deliver AC power from the nearest substation at about 7,200 VAC, and the 220 VAC that is usually available at the service entrance to a home or small business. Unfortunately, no HF user in his right mind expects the RF energy imposed on 60-Hz power to be confined to the power company's lines.
PSTN
The use of the public switched telephone network (PSTN) to obtain a communications capability is as ubiquitous as homes and offices that have electrical service. Although V.92 modems designed for use over the PSTN are stated as having a 56-kbps data transfer capability, in reality the maximum data transfer rate one obtains is typically between 41 and 44 kbps.
CABLE MODEM
Currently high-speed Internet access is dominated by the use of cable modem technology. During the late 1990s through the turn of the millennium, cable operators spent tens of billions of dollars upgrading their infrastructure to support two-way amplification of signals, which enabled the support of cable modem technology. Although cable modem service is now offered by just about every medium- and large scale cable operator it is not ubiquitous. Cable service usually bypasses businesses in shopping malls, strip shopping centers, and stand-alone business structures.
SATELLITE
Currently, Internet access via satellite represents a niche market, with less than a few percent of all Internet access occurring using this technology. Satellite Internet access is commonly used in rural areas where neither cable modem nor DSL services are available. Although Dish Networks spent approximately a billion dollars for the creation of a satellite that was to provide a significant increase in Internet access, according to the company decided to use the satellite for video operations, which put a damper on its expected growth in the data services
area.The company decided to use the satellite for video operations, which put a damper on its expected growth in the data services area.
BPL – The Alternative Broadband
BPL technology offers an alternative means of providing high-speed Internet access voice over Internet protocol (VoIP), video on demand (VOD) and other broadband services, using medium- and low-voltage lines to access homes and businesses. BPL’s technical feasibility has been demonstrated in more than a dozen field tests. BPL as a business is being tested for the first time in Manassas, Va., and Cincinnati, where BPL networks are being assembled to reach thousands of customers.
