View Full Version : 2 questions about network switch and cables

17-04-2004, 09:06 AM
Hi guys ^^

Just have 2 questions. Pretty easy question though I wonder why I dont know the answer to them >_< .

Well, 1st question is, are there only 2 types of cables for networking, crossovers and "patched" cables that comes in CAT5 or 6?

2nd question, if I brought a switch can I connect a computer to it with a crossover while another 2 computers used Patched cable say CAT5. Would all 3 computer be able to see each other? In other words can I connect to a switch with a crossover cable?

Any answers or comments would be great.

Thanks a lot guys :)

17-04-2004, 09:21 AM
1st The devices at each end are configured on whether they are connection point or an end point (a bit like master and slave). This means that a PC and a hub can be connected with a straight cable (and the crossover is done at the connector of the PC, if you like), but to get signals flowing between two hubs you either need a crossover cable or a crossover port on one of the hubs (not both, otherwise two crossovers make a straight).
Same applies to connecting two PCs directly, you need a crossover cable.

2nd you can connect a PC to a switch/hub with a crossover cable if it is plugged in to a crossover port (often marked with an X or maybe with a little switch so you can make it crossover or straight.

How's that?

17-04-2004, 11:07 AM
Cool, very cool. Thanks a lot for your answer ^^
Thanks for replying so fast too :)

17-04-2004, 11:33 AM
Some (but NOT all) switches have auto sensing and will reconfigure for a cross-over cable. If they do this they will be advertised as such.

Its unlikely that hubs will be able to do this, just some switches.

17-04-2004, 11:51 AM
Essentially, the switch/hub acts like a crossover cable... as long as you connect to it with a straight.

Graham L
17-04-2004, 03:45 PM
The tranceivers use two pairs of wires. One pair is the transmit pair,the other is the receive pair(as seen by each tranceiver).

If you connect two computers together directly, you have to use a crossover cable so that they are connected as TX-RX, RX-TX. TX-TX, RX-RX won't cause smoke; it just won't work.

A hub or switch is a "multiport repeater" Its connectors are wired in the"crossover mode" so you use straight cables to connect computers to it. The internal logic of a hub regenerates all the signals it sees on any of its RX pins,and sends them out on all its TX pins. If it's to be extended, you use either a crossover cable from one of its ports to another hub (to get the TX-RX, RX-TX) or has a switch on one port to swap the wires so you can use a straight cable.

If you're short of straight cables you could use a crossover cable from a computer to the link port.

A "patch cable" is normally a straightthrough one; it's called a patch cable because it uses stranded cable, rather than the solid conductor cable used for the fixed wiring. (The RJ45 plugs come in two types -- for solid/stranded cable -- and it matters which sort is used). Stranded cable is more flexible and stands up o handling better than solid. It's used from wallsockets to devices, or on "patch panels" which are used for organising big installations. A "crossover cable" will usually be made with stranded cable so it's a patch cable too. :D