PLC (Power Line Communication) Ethernet networking has been a real godsend for the people who live or work in a rented place. Especially when the edifice is owned by a tyrannical landlord who still lives in the Middle Ages.

"What, you wanna bore a huge hole through the wall of my dear apartment? For a cable? No, no way. Over my dead body you can!"

Of course, wireless 802.11a/b/g/n would be easier and relatively trouble-free. But when your computer and access point are separated by three concrete walls with lots of ironworks inside, things would start getting nasty. External antennae, boosters, relaying repeater stations, and so on. And wireless connection is rather sluggish, too.

PLC Ethernet works fine in this concrete jungle without any trouble. Simply plug in two adapters into AC socket, and LAN is ready. And connection runs far quicker than wireless, nominally 100 to 200Mbps, actually half of that value. Also, wireless can co-exist with PLC easily.

So far, consumer PLC has had a rather troublesome limitation. One group, consisting of a master adapter and plural slave adapters, could not exceed the magic number of 16 adapters. And only one group could share the power line. So if your office had some more LAN users, you would have to build a hybrid system using wireless and lots of hubs.

Now a network equipment merchant in Tokyo, ZyXEL Japan,, has somehow has broken this barrier. ZyXEL PLA-400 PLC adapters can have four groups co-exist on one power line circuit. Numbers of adapters in one group being the same 16, altogether 64 adapters can be connected in your office. Rather an improvement, though not a quantum leap.

PLA-400's maximum speed, 200Mbps, can be achieved only in the heavenly LAN where god works as a netmaster. You have to be satisfied with a more practical 85Mbps or thereabouts.

Handshake (communication and coding protocol) establishes automatically when two PLA-400s are plugged in. Building PLC network is really a kindergarten job compared with Wi-Fi or cabled job.

Everything else of PLA-400 is a regular PLC: Not significantly better or worse than other bunches of PLC. Even the price tag is identical to others; PLA-400 starter kit (one master adapter and a slave adapter) costs 18,000 yen (US$130). An additional slave adapter, 12,000 yen (US$97). Sure, building a large LAN using PLA-400 can be pretty expensive.

But, which is cheaper? Another choice is going to court with your enraged landlord who has just found several gaping holes in the walls of your rented unit.

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