Among the crop of video telephones on display at this year’s Communications ’92 show in Birmingham, the Mentec Video Server on Cimcon’s stand stood out. For one thing, it is one of the new set of machines that use the personal computer as their base, perching a small Charge-Coupled Device camera over the personal computer’s screen. But most unusually, the images and sound are passed over Ethernet and Token Ring, rather than the more conventional ISDN or leased circuits. Isochronous traffic over non deterministic protocols? Surely not. But the company, which is the UK distributor for the device, manufactured by Dublin-based Mentec Ltd says that there are no problems provided that the network is not heavily loaded. Certainly the 360 by 288 pixel display running at 25 frames a second over an Ethernet segment produced excellent results. Unfortunately, a single such link generates around 400Kbps – not the kind of thing that the average network manager would want clogging up the network. This is especially true since the prototype device on display sent the video in the form of NetBIOS packets, which is simple to implement, but being unroutable tend let packets leak all over a network. The production model, ready in a few months will fix this by wrapping the data in routable TCP/IP packets. Cimcon’s managing director, Colin Bowden, says that since scan rate is software selectable, the data rate can be trimmed to suit available bandwidth. But what of the market? Datapoint Corp launched its Minstral videoconferencing system that ran over ARCnet in the mid-1989s, without conspicuous success. Boden says that he was overwhelmed by the number of enquiries and says that much of the interest is being generated because local area network videoconferencing is poorly served; however Mentec people on the stand admitted that punters were interested in the ISDN interface that will also be included in a future version. Also in the pipeline is a version for high performance Unix workstations. Setting up the system is not, apparently trivial and for this reason Cimcon insists on supplying the first pair of devices as a finished system: the video codec, camera, local area network boards and 80486-based personal computer all bundled in for the non-budget price of #12,000. Once the site has got used to the technology, subsequent devices can be installed into existing pesonal computers, or volume users will be allowed to buy the component boards separately.
