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Why do we have cross-over cables.

J

Jeroen Belleman

Jan 1, 1970
0
Michael said:
Jeroen Belleman wrote:.


No, because it was designed to work, and meet the requirements at the
time.

Of course it works. That's not the point. The question was about
why we don't come up with an interconnect that doesn't require
cross-over cables. It's so nice, so simple.

As for requirements; We all know that 'requirements' are really
a mere description of the way the prototype behaved the day we
got it to work. ;-)

Jeroen Belleman
(Standards are merely intended to cripple competition.)
 
C

Capt. Cave Man

Jan 1, 1970
0
It would surely be much nicer if equipment at both ends of the link used
just a single pair to communicate in both directions, full duplex, too.
If the plain old telephone system can do it, why not data communications
equipment?

No distinction between DCE or DTE, only one single pair of wire, only
one type of cheap cable, cheap and simple connectors, no fuss, no
confusion.

Maybe it's this way because it was designed by a committee?

Jeroen Belleman

Consider the speed limitations of such a system.

Even fiber optic transmission (transception<sic>)has two paths.
 
C

Capt. Cave Man

Jan 1, 1970
0
Of course it works. That's not the point. The question was about
why we don't come up with an interconnect that doesn't require
cross-over cables. It's so nice, so simple.

As for requirements; We all know that 'requirements' are really
a mere description of the way the prototype behaved the day we
got it to work. ;-)

Jeroen Belleman
(Standards are merely intended to cripple competition.)

I'll bet that it has to do with the speed of the wire limitations at
the time.

This is a question for Floyd Davidson.
 
D

David Segall

Jan 1, 1970
0
Jeroen Belleman said:
The question was about
why we don't come up with an interconnect that doesn't require
cross-over cables.

No. The original post asked why we don't have an interconnect that
_only_ uses cross-over cables. The question has been answered on both
the historical basis of a clear distinction between "transmitting" and
"receiving" equipment and ease of manufacture of straight through
cables.

The modern trend has been to use a bidirectional interface such as USB
but this is necessarily slower than a similar interface using three
wires instead of two and a cross-over cable. Nobody has actually
answered the question in the current context.
 
J

Jeroen Belleman

Jan 1, 1970
0
David said:
Jeroen Belleman said:
The question was about
why we don't come up with an interconnect that doesn't require
cross-over cables.

No. The original post asked why we don't have an interconnect that
_only_ uses cross-over cables. [...]

Ah yes, that was indeed the question.
The modern trend has been to use a bidirectional interface such as USB
but this is necessarily slower than a similar interface using three
wires instead of two and a cross-over cable. [...]

I suppose you are thinking of half-duplex traffic. It's quite
possible to have full-duplex traffic on a single pair of wires.
There would then be no speed penalty.

Jeroen Belleman
 
J

Jasen Betts

Jan 1, 1970
0
It would surely be much nicer if equipment at both ends of the link used
just a single pair to communicate in both directions, full duplex, too.
If the plain old telephone system can do it, why not data communications
equipment?
RS485?

No distinction between DCE or DTE, only one single pair of wire, only
one type of cheap cable, cheap and simple connectors, no fuss, no
confusion.

RS232 was the solution to a different problem (how to conect modems to
terminals)
 
J

Jeroen Belleman

Jan 1, 1970
0
Archimedes' Lever said:
Actually, there WOULD then be a speed issue.

Oh, that's very helpful.
Would you mind motivating that statement just a little?

Jeroen Belleman
 
C

Capt. Cave Man

Jan 1, 1970
0
Just because you have not seen


EHHHH! Wrong ASSumption AGAIN, dumbfuckKK!
bidirectional full duplex on a single
fiber does not mean that it cannot exist.

I NEVER once said that it didn't or couldn't, you RETARDED, PRESUMPTUOUS
****!
I have used such devices.

Good for you, idiot. The remark was about what is in place and in use
NOW!
They typically use wavelength division multiplexing.
.

No shit. I knew what OC-96 was before you even knew what an optical
fiber was.
 
C

Capt. Cave Man

Jan 1, 1970
0
---
Nothing new there, it's the same as frequency division multiplexing.

The point is, though, for a medium of propagation with a finite
bandwidth, two channels can only exploit up to half the bandwidth each
if they're both active at the same time.

Or 90/10 or 60/40 or whatever, as long as the bandwidth of the medium
isn't exceeded.


JF

A San Diego company just recently got 'near wire speed' (unheard of) on
the new 10Gb/s standards being developed.

They got 8.5Gb/s out of it. That is better than anything current. Most
of the current stuff has far too much overhead. We are lucky if Gigabit
Ethernet can push 600Mb/s on a good day.

They did it with a Cell Broadband Engine CPU.

There will be Cell processors in our future.

Hell, if we make it past 12-20-2012 things will actually look good.

Maybe we'll close off the borders and kick some illegal immigrant
asses, and then clean up the gang problems too!

Maybe the horses will ride after all!
 
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