CAT5 and CAT5e Connection Capabilities

[PCV]

Over a recent debate on the capabilities of Cat5 and Cat5e cables, the Technicians over at TGH would like to have the following clarified if possible.

Can CAT5(or enhanced) run at 100mbits/sec with only 2 pairs connected? Keeping in mind that
these cables have passed certified testing and 10/100 switches are used throughout. We've been under
the impression that 2 pairs will only allow a connection of 10mbits/sec. Somebody tells us otherwise.

Also if its possible to explain the usage of each individual pair in a 100mbit connection.

Thx

 

[jimbopalmer]

10baseT uses 2 pair of Cat3 wires
100baseT4 (almost never used) uses 4 pair of Cat3 wires
100baseTX uses 2 pair of Cat5 wires, ideally Cat5e if full duplex
1000baseT uses 4 pair of Cat5e wires I tried to remain child-like, all I acheived was childish.

 

[daronwilson]

Two pairs will allow you 10 mbs or 100 mbs full duplex. Technically the 100mb full duplex should do fine on Cat5, I have a facility with 160 drops of 8 year old Cat5 running now on 100mb FD and it seems to do fine. Remember...Cat5 has a bandwidth of 100 MHz, so does Cat5e. Cat5e cable is built with much more headroom, but the standard only requires it fly at 100 MHz.

On 10/100 ethernet, one pair transmits data, and one pair receives data. They are balanced pair connections. The full duplex mode allows both transmit and receive to occur simultaneously. As I understand 1000baseT or Gigabit ethernet, the signal is divided up between all four pairs to achieve the desired speed.

Hope that helps, good luck.
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[PCV]

Great... thx guys