Well Billy Jo Ray Bob...Here is a relayed message from telephonics, as promised. Some of us actually deliver on our promises.
Almost any video vendor can deliver 30fps NTSC video over a local area network. Most, however, choose not to participate in the analog world. The point here is that category 5 copper wire is what is contained in a LAN cable. This cat 5 wire, although copper, is not the same as twisted pair telephone cable. Every multistory office structure I've ever worked in has had a large number of spare pairs of telephone wire installed when the building was built. There's and old saying in communications- the amount of traffic in any situation will grow to utilize the entire capability of a system. This is very true in telephony as well as in, for example, the internet. I have never found a building which has, during its construction, installed spare LAN cables. If one wants to use a LAN cable for video within a campus or within an existing building, he will find it quite expensive to install same.
Suffice it to say, major video vendors think digital is the standard of our new world. Remember, even in that domain, it took PictureTel about ten years to turn its first profit. Analog NTSC was ignored by the big boys until they saw the advantages in particular requirements that, digitally speaking, were either too expensive to implement or which couldn't match the 30fps standard. This is no longer true. There are many, many smaller vendors offering analog video conferencing systems today. Even PictureTel now has an offering which allows analog transmission over POTS.
SEXI has, to my knowledge, never demonstrated a "line diver" other than the Lightwave product, which they can no longer obtain. The Lightwave device enables transmission of 30fps, full color, full motion NTSC video (this is what you get on your home TV set) for up to 4000 feet from the non-blocking matrix switch to which it is connected. It is not possible to use a repeater in a line equipped witha Lightwave tranceiver. What I think you meant to convey is that a PC (in a Lightwave system) connectedto a switch could then video conference with any other PC connected to that switch up to another 4000 feet over twisted pair telephone wire. This then says-that PC's in such a system could be up to 8000 feet apart and still utilize 30 fps video.
There are a variety of line drivers available which approach the distance criteria which Lightwave is capable of demonstrating. None reach the 4000 feet but there are several available which could provide NTSC transmission over twisted pair to about 3000 feet. Many systems employ a type of line driver (RF) which drives analog video up to 100 meters, which is adequate in many applications. See Datapoint, C-Phone etc etc etc.
The demonstration system which SEXI acquired from ICMX was produced by Lightwave and was not an ICMX product which they developed.
Telephonics |
