CAT6 Cabling for computer to computer

[Astroman]

Hi all,

When I hear about people using a CAT6 cable between computers in an obs or whatever, what type of cabling are you using, a normal CAT6 Patch Cable or a Crossover Patch cable?

Also is there a way to use a standard Cat6 patch cable to connect the computers for remote use? ie. I want a small computer in obs to do the telescope control, image capture (onto the inside computers HDD) etc..., and use the inside computer to do the image processing.. Is there a way around this?

[dannat]

andrew how far is the outside? r u running the cat6 in conduit under ground or along a roof out

would a basic router work for you?

[Astroman]

Well from computer to computer it would probably be about 4 metres Max :-) but I didn't want to use wireless if I could get away with it. It will be running through conduit from shed to the obs just under the ground.

[rogerco]

Given the low cost of a small network hub (switch) why would you bother with cross over cables which at best will only connect two devices. Jaycar has 8 port switched from $25. If you setup a small network like this you can do anything.

[Astroman]

What sort of cables are used on these switches Roger? I havent used anything like that before.

[entity62]

Andrew, you do not need to use cross over cabling for a Network switch. The switch handles the cross over for you.
I run 30m of Cat5 to ob's and then connect to switch, and then plug my 2 Ob's PC's into it.
The other end of Cat5 plugs into my moden/router, so i can surf the net while looking at live image on other PC.
MSY at Elizabeth has Switches starting at $12. 10/100 switch.
Gotta love this tech.
Darrell

[lacad01]

In answer to original question, back to back PC to PC connection needs a crossover cable. As others have said, a small switch or hub alleviates the need for the crossover and normal straight through Cat5 or 6 patch cable can be used.

[GrampianStars]

G'day Andrew

Data cables:
Cat 5e runs @ 100MHz bandwidth
Cat 6 runs @ 200MHz bandwidth
Cat 6e runs @ 250MHz bandwidth

All use the same Industry Standard RJ45 connectors
Don't be fooled by the sales jargon
Just buy the Cat 5e connectors @ 1/3 the price :thumbsup:

[Astroman]

Thanks for all your replies, certainly something to look at. I already had the Cat6 cable thats why I was asking, I have a couple of other short length CAT5 cables too.

Having other issues with my Main PC atm, so this will be looked at once the PC is fixed... Thats another story...

[mithrandir]

Going back to the original question, does one or more of the PCs have gigabit ethernet?

If it does, it does not matter whether you use a straight through or crossover cable. Gigabit ports MUST be able to work out the correct signalling.

If neither is gigabit and you do not want a hub/switch you must use a crossover cable.

If the run is short Cat5E is fine. For longer runs at gigabit Cat6 is the better bet.

If you were buying a switch, get gigabit. The slight extra cost beats worrying about what sort of cables you need.

FYI if you were getting close to the 100m limit for ethernet you should get most of it (up to 90m) run in solid core Cat6 to RJ45 sockets and use two stranded core fly leads no more than 5m each to the PCs.

[Astroman]

Thanks for the info, I ver much doubt these PC's will have a gigabit ethernet, they are a little on the older side of technology

[Steffen]

Aren't network interfaces usually auto-sensing these days? I truly can't remember the last time I had to use a cross-over cable to connect two computers back to back.

Cheers
Steffen.

[mithrandir]

Steffen, gigabit is the only interface where cable autosensing is a MUST requirement in the standard. 100Mb might but that would be a non-standard extension by the manufacturer. It only takes one end of the link to support cable autosense for it to work.

Speed is another matter. Gigabit MUST be configured auto speed and duplex. Lower speeds can be fixed at 10Mb or 100Mb and full or half duplex. Getting this wrong is a great way to stuff up your network.

[Steffen]

That's what I mean. So, unless the PCs in question are older than five years or so cross-over cables shouldn't be required, right?

Cheers
Steffen

[rogerco]

I think the others have answered the question. A simple network is pretty easy to set up but it helps if everything is the same, same speed cards and switch and the same version of Windows on each machine. Windows has utilities built in to auto-detect network architecture butit tends to only work transparently if its all the same version of windows.

Good luck
Roger

[Astroman]

I think I will look at getting that switch, seems like an easier solution than one cable (which I don't have) so I can use the cables I do have. Thanks for all you guys input it made the choice so much easier... I guess the saying "there is more than one way to skin a cat", works well here...

[mithrandir]

The other way round Steffen. If both PC ethernet ports are 100Mb or slower you will need a crossover cable.

I've got Cat5 (it has been there a long time) going through the ceiling. I had to put a 100Mb switch in SWMBO's study to force her PC to 100Mb, since the cable is not really up to the 1Gb that the boxes in my study use.

[Steffen]

Yes, which I thought was synonymous with "five years or older" ;)

Cheers
Steffen.

[Merlin66]

Hmmm
Reading this thread has made me think about the set-up I have...
The ol' Acer (XP) in the observatory is connected with Cat 6 (was originally around 80mtr) to the wireless/modem hub in the office.
I then have a Cat5e (why? well that's what came with the wireless install) connected to the Dell (also XP).
I use Teamviewer to remote control the Acer and download the image files etc etc.
Then there's the "boss's" Aspire (Win7,64) connected also to the wireless network and runs Teamviewer as well.
Everything seems to work very well - no issues, no problems.

[alistairsam]

hi Andrew,

if you can't get a crossover for that length, a simple solution is to use a cat5e or cat 6 straight through, an RJ-45 coupler and a half metre crossover at the end. may sound dodgy but technically no issues and we use it all the time in the field as a last resort. Eliminates the need for a switch.

once the link lights come on, just assign static IP's for each of the PC's in the same subnet.
if you wanted to extend your wi-fi internet, use ICS on the "inside" PC.

Other option is to save all images to the Obs PC, and transfer them in the morning.

Cheers

[Astroman]

I guess I wouldn't be able to use an old wireless modem as a switch could I?

[Astroman]

I guess I wouldn't be able to use an old wireless modem as a switch could I? I got a wireless modem here with 4 ports on it. Don't need the internet bit on it as the main computer already has a wireless link to my house computer.

[mithrandir]

The answer has to be "maybe". The software in the modem may or may not let the two computers communicate without a working uplink, and you have to get the configuration right in the PC with the wireless link to the house.

Can you put together a diagram with all the devices? Something along these lines. My two laptops still put up a fight about having two network links.

[Poita]

Yes, with just two computers you can do this with just a standard CAT6 cable or a crossover cable (all my computers auto detect and will use either YMMV).
It is just a matter of setting the IP addresses and sharing the relevant folders, and you can use remote access software (free) that will allow you to control either computer from the other if you don't want to get out of your chair!

Otherwise, as mentioned, get a small 5 port gigabit switch for $28
http://www.pccasegear.com/index.php?main_page=index&cPath=200_331&vk_sort=1

You may as well get a gigabit switch at that price. It will work with 10/100 anyway, and if you do move to gigabit the file transfer speed is way way faster. If they are desktops then Gigabit cards for them are about $10 each.
http://www.pccasegear.com/index.php?main_page=index&cPath=200_328&vk_sort=1

[alistairsam]

Hi,

Sure you can. as long as you don't connect it to the WAN port.
the 4 ports are usually a switch or a hub, so no reason you can't use it as it'll work at layer 2. you could easily test it and will save you buying one.
what's the make and model of the wireless modem?

Cheers

[Astroman]

It looks like our old modem was given away to someone so I dont have it anymore. Was looking forward to trying this out. Looks like I am going to have to get a switch.

[alistairsam]

hi

have you checked if you can get a 4m crossover?

[Astroman]

Not yet will check on weekend. Had some health issues so will check it out then.

[mithrandir]

You might find a small gigabit switch is cheaper than a cross-over. They sure known how to charge for less common cables.

[Astroman]

Jaycar have a 10M CAT5e crossover lead for $16.