Ethernet cable with only 4 cables?

[Eton]

So I've been thinking about running a dedicated ethernet cable to my pc so I can get full use of my 50MB/s connection. Then I realized instead of running a new ethernet cable I could just replace the jack on a old phone cable because it runs straight to where my modem is. The only problem is theirs only 4 cables, that wouldn't be a problem, would it?

[Lurick]

If the cable is Cat5 or better cable then you'll get up 100Mbps with 4 wires but if you ever want more than that you'll need all 8 wires and Cat5e cable or better rated cable.

[Eton]

2 minutes ago, Lurick said:

If the cable is Cat5 or better cable then you'll get up 100Mbps with 4 wires but if you ever want more than that you'll need all 8 wires and Cat5e cable or better rated cable.

So theoretically it should be able to handle a 50Mbps with no problem?

[Electronics Wizardy]

also if its a old phone cable there is good chance that it might not handle high speeds well. Phone cables aren't made for high bandwidth.

[Lurick]

Just now, Eton said:

So theoretically it should be able to handle a 50Mbps with no problem?

In theory, yes.

[mariushm]

In theory, it could work at 100 mbps as long as you crimp the wires in the proper locations :

 

You want the four wires in the positions 1,2, 3 and 6:

1,2 are one pair of wires, used to transmit data ... 3 and 6 are the second pair of wires, used to receive data  ( or the other way around, receive/transmit, doesn't really matter)

In order for the network card to connect at 1gbps, all 8 wires must be present.

 

It may work over a very short distance, but normally in order to transmit and receive data up to 100 meters as the standard says, the pairs of wires have to be twisted around and must have a certain number of twists per inch, the cables are somewhat precise.

The regular 4 wire phone cables don't usually twist the pairs of wires inside and also the wires themselves are much thinner, so I suspect you'll have difficulty actually crimping RJ45 connectors to those wires.

Maybe if you install an ethernet socket and then you plug a regular ethernet cable in that socket....

 

 

[Mira Yurizaki]

31 minutes ago, Eton said:

So I've been thinking about running a dedicated ethernet cable to my pc so I can get full use of my 50MB/s connection. Then I realized instead of running a new ethernet cable I could just replace the jack on a old phone cable because it runs straight to where my modem is. The only problem is theirs only 4 cables, that wouldn't be a problem, would it?

Looking at the pinout for RJ45 (https://en.wikipedia.org/wiki/Modular_connector#Pinout_3), it only needs four wires to get 100 Mbps. (pins 4-5 and 7-8 can be ignored)

 

Though the old cable may not be good enough for long distances.

[Slayerking92]

And if the cable isn't twisted pair,  It won't work if its a long cable run.