Cat 5 manual switches

[Ron Lowe]

Hi, all.

I'm looking for a simple 2-port cat-5 on/off box. Well, actually, I want a 2-pole version ( 2 in, 2 out. )

This is to switch the uplink port from a classroom switch off whilst class is in progress, to shut down all IM, skype etc, whilst leaving the class as a stand-alone island. The second pole is to isolate the Wireless Access Point too.

We currently just pull the uplink cable from the switch and WAP, but the PHB wants a 'classroom network on/off switch', which he feels is 'better' than pulling a patch cord.

A managed switch and logging into it is not what we are looking for. ( Non-PHB compatable. ) I could use a hardware firewall, but that also is not PHB-compatable, and also pushes an admin burden my way.

So what we're going to do is install a simple on/off switch on the uplink and WAP. I'll make one myself from parts, but would rather just buy one.

But googling 'cat5 switch' naturally produces the wrong kind of thing. I've tried various other search options, but nothing like what I really want. I suspect I'm heading down the self-build route....

[PeterK]

Have a look at

They have manual RJ45 switches on this page but I'm not sure if they are isolators and look expensive. They may well be worth contacting for a solution - see free call back top right on page. PeterK

[Rick]

You need a decent firewall, that automatiocaly does what you want at pre-defibed times. You can also configure it to block all sorts of nasties.

R> Hi, all.

[dmc]

Sticking a physical switch into cat5 isn't likely to really be a good idea - you'll get a way with it but I'd not want to look at the error counts to closely.

Wouldn't a small switch (of the ethernet type) in the uplink path that is easily powered on and off using a power switch on the wall be a better option?

You could even label it "teh interweb" so phb would understand.

Darren

[Ron Lowe]

Yes, that's an option I had not considered. I quite like that. Thanks.

[Anthony R. Gold]

Try:

for a £10 solution including postage and then switch the mains on and off.

Tony

[The Natural Philosopher]

Justs short out the wires. The signal is on two pairs and you can just break a cable apart and solder it to a double pole switch that shorts the two active pairs. that shouldn't degrade it much when the switch is open, but will muller it nicely when its closed.

[The Natural Philosopher]

If you don't want to solder, thats about as simple as it gets.

>

[Lurch]

On Fri, 31 Aug 2007 04:59:14 +0100, The Natural Philosopher mused:

Not the best idea for a professional solution IMO.

[dennis]

Does putting it in a plastic box with a couple of RJ45 sockets make it more professional? Just watch out for power over Ethernet although shorting them shouldn't do any harm it wastes power.

The idea of the Ethernet switch, combined with a time switch, works fine.. been there and done it before now. I have even put a time switch on an AP before now but that was to prove that the AP didn't give someone headaches as they claimed.

[The Natural Philosopher]

exactly.

yup. ethernet itself is able to handle shorts..

i've tucked THAT one away for future use..

Once we did a Very Big ISP installation for a telco. One of the things they demanded was 'a relay that close when Something Is Wrong, and another relay that will close When Something is really Badly Wrong..'

This, apparently could tie into their system of fault monitoring and light alarm lights on a panel..for the operators to investigate.

Well it turns out thats its actually rather hard to find a bit of hardware that goes in a SUN SPARC that will 'close a relay' and moreover, if the sparc itself crashed, close the relays..

we ended up with some hand etched PCB's and a parallel port attached to the SPARCS parallel port such that only by repeatedly sending an 'all clear' signal down the port, the relays would be held open..any power failure or lack of signal would close one or both of them. They looked horrible, but we mounted them in a little card frame and put them in a card rack, and they looked MUCH better. I wrote a crappy daemon that did a poll? Ok? send all clear? sleep 20 seconds? loop...

We put one on one of our machines to ping various targets round the internet..and I wrote a web page that drew a picture of the links and marked the dead ones in red..

It was a hot to see the red light come on and fire up the page and say - 'ah yes, Pipex is fscked again'

Professionalism is in the eye of the beholder. It worked. hat was all that was wanted.

[Chris Hodges]

A clasic if crude watchdog circuit - what about its own failure modes though?

For the OP, if you're going to short the lines, a capcitor and resistor in series would surely be better than a dead short - I know the upstream hardware should be able to handle it, but long term, who knows (whatever the spec says).

If you want to do a fair few lines at a time, you could gut an old parallel port T-switch for parts, and it would come with a free housing, but perhaps the PHB wants a keyswitch.

[Ron Lowe]

Yes, I'd considered cannibalising an old centronics switch and making something up. But that involves some work.

I rather like the 'small switch in the uplink path that can be powered off' approach. I can wire the Wireless Access Point to that too.

[Frank]

Is the WAP connected to a port on the switch? If so then switching off the electrical supply to the switch would disable both!

[dennis]

Ethernet can handle a short forever without damage.. after all it is just a transformer at each end of a bit of wire.

[Ron Lowe]

The mains supply into your house is just a transformer and a couple of bits of wire. Don't fancy shorting that.

[Andy Dingley]

Since when did Ethernet (any flavour) use transformers?

[Andy Dingley]

Why not? It's a far better solution (as something to do to a transmission line) than any practical way of opening the circuit rather than shorting it across.

[Van Helsing]

since always...

they're used to provide eletrical isolation between the PC and the cabling.

They don't look like the typical transformer these days. The are small and set in some type of resin - looking much like and oversized chip..

VH

[Lurch]

On Sat, 01 Sep 2007 21:06:35 +0100, Andy Dingley mused:

Note the words 'for a professinal solution'. I didn;t say it wouldn;t work, or wasn't a good solution, but I wouldn't use it outside of my own home network if I did ever do it.