xDSL through USB, & IEEE 1394

Gentle Readers,

I have told you folks quite a bit about xDSL technology, but how is it really likely to enter the machine. Most new machines have at least one USB (Universal Serial Bus) port on them, mine has a couple.

To date only high-end video equipment has implemented any of this through proprietary software and technology. Let me explain.

USB is a technology that came up as a joint effort of several companies; Compac, DEC, IBM, Intel, Microsoft, NEC and Northern Telecom. Notice that is a list of the "biggies!" It has to speeds, roughly. One is 10 to 100 kbps (kilobits per second) for interactive devices like games and some VR. The one that is next, and of the main interest is 100kbps to 10Mbps (Megabits per second) that is actually done with a 12Mbps transfer called NRZI (non-return zero inverted) encoding. There is also a 1.5Mbps sub-channel that can be used simultaneously. The numbers definitely support any xDSL technology but the highest speed.

IEEE 1394 (FireWire) is compatible though faster; running at up to 100Mbps. This is video's domain.

Naturally there exist a pair of *rubs* in the works. First is two implementations of the HCI (Host Controller Interface); this is what is in your PC. One is UHCI (Universal...) that is Intel's and works on its chips. The other OHCI (Open...) and developed by Compac, Microsoft and National Semiconductors.

Second, and would you not just know it, the WDM (Win32 Driver Model) for Win95, OS97 and WinNT from Microsoft is behind schedule. The first one is solvable in hardware by design techniques that will recognize and identify the device. These devices are also hot-pluggable if designed correctly. Your PC will poll them, recognize them and give them one of 127 addresses when plugged in.

It is achieved over a four wire system; one pair carries data only while the other is capable of carrying data and power to the peripherals. Well, enough except for URLs.

Universal Serial Bus Consortium

Intel

Motorola

Mindshare

And my source was Embedded Systems Programming

Peace,
Clarke