Crossover cables - is there a maximum length?

  • Thread starter Thread starter amart
  • Start date Start date
A

amart

I am connecting 2 win2k pc's using a direct connection crossover
cable.

It all works fine with my short 2 metre cable, but I cannot get it
working with a long 30 metre cable (I have tested the long cable with
a multimeter and it looks fine).

When I plug it in it takes about 20 seconds for the network cards
small led light to turn on, then the connection shows up on the tool
bar saying it is 100Mbits. Both pc's try to talk, ie. they send
packets, but no response, neither one receives packets.

Is this because the cable is too long? Do i need a straight cable
through a hub to be able to go over this distance, or could it be
something else?

Many thanks.
 
amart said:
I am connecting 2 win2k pc's using a direct connection crossover
cable.

It all works fine with my short 2 metre cable, but I cannot get it
working with a long 30 metre cable (I have tested the long cable with
a multimeter and it looks fine).

When I plug it in it takes about 20 seconds for the network cards
small led light to turn on, then the connection shows up on the tool
bar saying it is 100Mbits. Both pc's try to talk, ie. they send
packets, but no response, neither one receives packets.

Is this because the cable is too long? Do i need a straight cable
through a hub to be able to go over this distance, or could it be
something else?

Many thanks.
Click to expand...

The cable may be incorrectly terminated, i.e. each
wire must be connected to the correct pin in the RJ45
connector.
 
I am connecting 2 win2k pc's using a direct connection crossover
cable.

It all works fine with my short 2 metre cable, but I cannot get it
working with a long 30 metre cable (I have tested the long cable with
a multimeter and it looks fine).

When I plug it in it takes about 20 seconds for the network cards
small led light to turn on, then the connection shows up on the tool
bar saying it is 100Mbits. Both pc's try to talk, ie. they send
packets, but no response, neither one receives packets.

Is this because the cable is too long? Do i need a straight cable
through a hub to be able to go over this distance, or could it be
something else?

Many thanks.
Click to expand...


30 meters (100 ft) is pretty close to the maximum, especially if it is an
older (Cat 3 or 4) cable. Make sure that you are using Cat 5 cable, and
that it is correctly wired as a cross-over.
 
Maximum distance between the Ethernet nodes using UTP cable either Cat3, 4,
or 5 is 100 meters (straight line). 1000BaseTX over Cat5 length is 25 meters
but yet 100 meters over Cat5e.
Ensure you got Cat5 rated jacks and cable. Aside of bad cable/jacks, it was
always the cheap/built-in NICs in my experience.
 
I thought the limit was 100 meters for 100BaseT. I don't think it changes
because the cable is a cross-over.

Oli
 
Jay Somerset said:
Sorry -- I always seem to get metric/standard conversions inverted.
Click to expand...

The length of 100m is for a perfectly terminated cable under perfect
conditions. A poorly terminated cable such as an incorrect wiring pattern
or just a "sloppy" job using a correct pattern can reduce the usable length.
Also outside interference (fluorescent lights, power cables and lines) can
also limited the distance.
Click to expand...
 
Ha! Hadn't thought of that. I have had mice ge into some things here. I
have some of those ketchup, mustard, etc., packets left over from lunch
sometimes,..they've chrewed those open and the stuff ran all over the
shelves at times,....which,..hmm....could draw Bugs? :-)


--

Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com


Steven L Umbach said:
Rats can be a problem also. --- Steve
Click to expand...
 
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