Home > Uncategorized > Goodbye, old RJ-11…

Goodbye, old RJ-11…

March 7, 2011

I spent the better part of the day installing VOIP phones in our offices today. They work over Ethernet lines; you unplug the computer connection, plug it into the phone, then use another cable from phone to computer.

Ethernet cables use an RJ-45 connector; it looks like a phone plug (RJ-11) only with eight lines instead of four. This means the phone has two fat, relatively inflexible cables coming out of it instead of one thin, flexible phone line. Our building, 6 years old, is the last “new” building on campus to be wired with RJ-11 wall jacks; from now on it’s all VOIP and CAT-6 Ethernet.

I have cable crimping and testing tools for RJ-11, RJ-45 and coax. Where copper is concerned, it looks like RJ-45 is the last one standing and will be around for a long time. Guess I should also learn how to terminate optical fiber. Which is interesting stuff, by the way; it is made from two kinds of glass having different refractive indexes, supported in a plastic tube.

Today I got a chance to look at some CAT-6 Ethernet cable. Very cool: it uses four twisted pairs of different periodicities, which are in turn twisted around a spiral plastic core that separates them to limit crosstalk. It should be able to carry a hell of a lot of signal. And I love the way the standard describes maximum run-length (37m) when used as 10GBASE-T; “Hostile Alien Crosstalk Environment”.

Traditional POTS (Plain Old Telephone Service) lines, as simple as they are, have traditionally been one of the most reliable technologies in our lives. Not as reliable as a hammer, maybe, but almost. Ethernet networks are less reliable. If the power goes down, we have only about 15 minutes of phone service before the UPS in the telecom rack goes dead.

But it isn’t as bad as all that. Most people have cell phones today, so a power outage won’t likely cut them off. And the VOIP phones can integrate with software phones. Faculty and staff can load a mobile application on their laptops, and re-route their office phones directly to the laptop. Because you know, we never want anyone to take a day off for any reason. Sick? Don’t stay in bed; work at home!

By the end of Spring break, we’ll have all our phones converted. The old Erikson phones are stacking up in a room somewhere on campus – probably tons of them along with obsolete switching equipment. They served very, very well. I just hope they’ll be properly recycled; that’s a hell of a lot of plastic, lead, and other toxic stuff. It puts me in mind of the huge numbers of TV sets I saw put out for trash after the switch to digital.

Think we’ll ever learn to plan for proper disposal/recycling as part of tech changeovers?

Categories: Uncategorized
  1. March 10, 2011 at 23:41 | #1

    I love the old phones. The old phone system was designed to work reliably. VOIP isn’t.

    My favorite way of illustrating the problem is picking up a VOIP phone receiver, handing it to someone, and saying “The network’s down. Call the NOC.”

    Ain’t progress great?

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