The last time I checked, the university optical system was still supporting Fast Ethernet between buildings. The 1985 units... I have a couple of those in my office now. I use them as ornaments; they make for some great war stories. When the client outlived their speeds (after installing a fiber-based MAN), they retired them and asked me if I wanted to hold on to them. As memorobilia. Packratitis Me, I gladly accepted. (Hi Graciella!)
Optical standards for fiberless (free space). You mean, as in interoperability? There are already gloms of standards that they must comform to, mostly those which apply to power levels from LASERs. But from what I can tell there is no standard modulation scheme employed that would lend to interoperability at this time.
I misrepresented in my previous post, in a way, when I noted that the Silcom unit was both ATM and Ethernet capable. I made it sound, in retrospect, that these units spoke the protocols. They do, but on the back end. On the air interface they are protocol agnostic. Most free-space system simply provide a carrier that is modulated in one way or another at the selected speed and protocol of choice. Actually, the university model also falls back to 10 Mb/s Ethernet. But it's protocol agnostic. It doesn't really care how you modulate it. That's a function of the interface to the LAN, on the back end of the transceiver.
Other systems can be used for both digital data applications and for amplitude- or frequency- modulated analog TV systems, for surveillance, program purposes, etc. And these are put together, from a modulation standpoint, in much the same way as systems that support analog voice and video over fiber. Not PCM, but AM/FM. |
