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What is the true cost of bandwidth? Not the price, but the actual cost. It used to be very expensive to provision a T1 over copper. It took a lot of manpower and equipment. Bridge taps and loading coils had to be removed, repeaters had to be installed, and it required two high-quality copper pairs. Modern technology (HDSL2) can do the same job, on a single pair, without line conditioning, and without repeaters for many spans. The cost of providing a T1 circuit is much lower. At the termination point, the data can be muxed on high-capacity fiber for transport to the Network Service Provider. I don't know what the costs are for transporting data over fiber, but I think it is safe to assume that improvements in technology have also reduced those costs.

I suspect Zilog and their bond holders were expecting their IPO to bail them out, but they withdrew it September 2000 when the IPO market went down the tubes.

Whois for "powerline.com" returns names with e-mail addresses on "powertrust.com". Whois for "powertrust.com" returns some of the same names and addresses, with e-mail addresses on "powerline.com". So we can conclude that "powerline.com" and "powertrust.com" are under the same ownership. There's interlinked domain ownership with "powerfulnetworks.com"(an ISP), and "powerinternet.org". (Clearly, these guys like "power").

Most of these organizations are located at 1701 S. Mays St, #J-121, Round Rock, Texas. At the same address are Gino's Pizzaria (#B), Eyecare Vision Centers (#R) , and My Choice Liquors (#N). Aerial photography confirms this is a mall. The "J-121" probably indicates some kind of mail drop, although it's not a MailBoxes Etc. location.

Going to "powertrust.com", we see just a logo and the tag line "The possibilities beyond the power". The page description for that page reads:

• PowerTrust.com is an Internet-based energy company offering savings for homeowners and small businesses. PowerTrust.com also offers such beyond-the-meter benefits as low-cost Internet access with no long-term contracts, domestic long-distance telephone rates for a flat 5.9 per minute anytime day or night with no monthly fee, and discounts on other home products and services.

So they have a full range of vaporware services.

PowerLine itself is at 11180 Sunrise Valley Drive, Reston, VA, which is an office building. "PowerTrust" is also at that location - listed as an oil and gas company.

Digging further, it gets worse. PowerTrust is in trouble for "slamming" natural gas services, switching customers to their service without authorization. They've "withdrawn" from the Washington DC area gas market, with the "encouragement" of the local regulatory authorities. It's not clear that they did any physical delivery of gas; it just seems to have been a remarketing thing.

A press release from PowerTrust indicates that PowerLine is a business unit of PowerTrust. It's supposedly a "joint venture with 'M@innet.net'", which provides the power line networking technology. Can't find "M@innet.net" in anything but PowerLine press releases, though.

So that's a brief rundown, and it doesn't look good.

This doesn't mean the technology is out of reach. There's a consortium for power-line networking: HomePlug. There's an evaluation kit available from Intellon. Includes source code for Linux drivers. Speed is around 8Mb/s now. They hope to get to 50Mb/s in a few years.

Lower speed systems are shipping. Easyplug, at 2Mb/s, is available now.

Like DSL, this is one of those things that just barely works because the transmission medium is so noisy, but can be made to work with very elaborate modulation techniques. Here's how HomePlug does it.

More technical info on the HomePlug standard can be found here (3000 words).
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Don't know about you, but a device that modulates multiple analog frequencies for upstream and downstream communications is called a MODEM [modulator/demodulator] in my neck of the woods! ADLS does this as does Cable. It's a modem that has a different frequency range, and tries not to step on either your existing voice range or cable TV range.

Hint -- That's why you only need one line for DSL and phone. Between you and the CO you can utilize far more frequencies on the UTP wire than the PSTN will allow thru the switches. Once your signal gets to the CO, the DSLAM creates a real digital stream [de-modulates the analog signals]

See these links for a good overview of ADSL technologies that Communications Systems Design published a couple issues ago:

Part I - ADSL Physical Layer
Part II - ADSL Handshake/Upper Layers


Your nitpick is correct with ISDN, but incorrect with ADSL. ISDN is a truly digital signal, and the CPE devices are called Terminal Adapters. Perhaps HDSL and IDSL are different, but ADSL and Cable technologies are not true digital signals to/from CPE......so the devices are called modems. ISDN is pretty much dead, but I seldom hear folks call the CPE device for ISDN a modem.

Don't know about you, but a device that modulates multiple analog frequencies for upstream and downstream communications is called a MODEM [modulator/demodulator] in my neck of the woods! ADLS does this as does Cable. It's a modem that has a different frequency range, and tries not to step on either your existing voice range or cable TV range.

Hint -- That's why you only need one line for DSL and phone. Between you and the CO you can utilize far more frequencies on the UTP wire than the PSTN will allow thru the switches. Once your signal gets to the CO, the DSLAM creates a real digital stream [de-modulates the analog signals]

See these links for a good overview of ADSL technologies that Communications Systems Design published a couple issues ago:

Part I - ADSL Physical Layer
Part II - ADSL Handshake/Upper Layers


Your nitpick is correct with ISDN, but incorrect with ADSL. ISDN is a truly digital signal, and the CPE devices are called Terminal Adapters. Perhaps HDSL and IDSL are different, but ADSL and Cable technologies are not true digital signals to/from CPE......so the devices are called modems. ISDN is pretty much dead, but I seldom hear folks call the CPE device for ISDN a modem.

Most processor vendors use MIPS as a performance indicator. Unfortunately, MIPS is a misleading unit because of the varying amounts of work done by instructions on different processors. For example, the C62xx instruction execution rate of eight RISC-like instructions per clock cycle (1,600 MIPS at 200 MHz) cannot be directly compared to the MIPS performance of typical DSP processors. This is because a MAC operation consisting of one multiplication, one addition, and two address calculations is implemented as a single instruction on conventional DSP processors, but as three to four instructions on the C62xx. Thus, a 200-MHz C62xx has performance comparable to a conventional DSP running at 400 MIPS to 1,000 MIPS.