MultiPort/LT Guide

Structured Wiring

Modern office buildings are fitted with a central wiring closet to house the network routers, hubs and communications equipment; and radial twisted-pair wiring to each individual workstation. This is somewhat at odds with LocalTalk’s daisy-chain topology. An easy compromise is to locate your MultiPort/LT in the wiring closet, fitted with four LocalTalk PhoneNET Adapters, providing eight radial connections to your various work areas. You then use LocalTalk daisy-chains to link small groups of workstations within each individual office and arrive at the recommended 10 to 15 nodes per MultiPort/LT port.

Alternatively, you may decide to interpose LocalTalk hubs or star controllers in each subnet, providing an individual radial connection to each workstation, and so conform fully with Structured Wiring conventions.

Tip: To accommodate 10Base-T Ethernet, structured wiring systems typically employ 4-pair RJ45 connectors. These are physically wider than the 2-pair RJ11 connectors used by the LocalTalk PhoneNET system. Fortunately however, the narrower RJ11 plugs are mechanically and electrically compatible with RJ45 sockets. LocalTalk, Ethernet and even regular telephone connections may be freely intermixed in structured wiring systems.

Do you really need Ethernet?
Even with congestion out of the way, it is still true that LocalTalk has a fundamental bandwidth limitation of 230Kbit/sec, versus a theoretical maximum of 10MBit/sec for standard Ethernet. In point of fact, LocalTalk speed is sufficient for most office and classroom situations. It is equivalent to four multiplexed ISDN B-channels. It is no obstacle for printing, electronic mail, and small file sharing. And, it is not generally a significant factor in the end-to-end performance of Internet browsing software such as Netscape Navigator, where such factors as remote server congestion or pipeline congestion are more likely to dominate.

LocalTalk would not be appropriate for applications requiring raw bandwidth, such as live video or frequent transfer of very large multimedia files. In these cases, even 10MBit/sec Ethernet is frequently inadequate. The fact remains that basic LocalTalk bandwidth is more than adequate for a typical user.

Only some of the more recent Macintosh computers come equipped ready for 10Base-T Ethernet. Depending on model, average cost for a 10Base-T Ethernet interface is $100. Many Macintosh models need to be disassembled to install adapter cards, which entails the cost of skilled labor. Special structured cable runs must be installed from each and every workstation to a central wiring closet. Hubs are required with enough ports to receive each and every radial cable run. To do all this from scratch will cost you between $500 and $1000 per connected computer.

By contrast, the Webster MultiPort/LT allows you to build fast, efficient LocalTalk based networks. MultiPort/LT enables you to route between four independent LocalTalk subnets, and to the corporate Ethernet backbone. With a conservative 12 or 13 nodes on each subnet, around 50 Macintosh computers can be efficiently networked at a total cost of around $50 per connected computer.

At many sites, structured wiring systems have already been installed, which is required in any case for PC’s, Unix workstations, and Macintosh users with heavy bandwidth needs. In these situations, there are still cost and other benefits in using MultiPort/LT and LocalTalk for the remaining Macintosh computers.

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Last updated March 21, 2005
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