Found this one http://www.taltech.com/r_tutor.htm
Not as much fun as the tutorial I once had, but every bit as explanatory.
Correct what I said below. Pin 4 =RTS pin 5=CTS misremembered pin 6 DSR ( on
the 25 wire RS232 )
In any case, good to review this stuff once in a while. It all comes back
now.....
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
Chuck Larrieu
Sent: Thursday, August 10, 2000 8:54 PM
To: Leigh Anne Chisholm; Yee, Jason; Cisco@Groupstudy. Com
Subject: RE: cross or straight?
Well, that was fun. I just spend a few minutes searching this old PC for a
neet little program I downloaded from Compuserve many eons ago. It was a
tutorial on data communications, complete with colors and flashing lights.
Got it back in the days when... never mind....
Didn't find it. May well be that it is on that old NT Web server that was
also my backup server. That machine has been off line and in a closet for a
while, and no prospects for firing it up any time soon. The program itself
talked about and demonstrated the voltage changes as a result of signaling
on the wire. Talked about pins 2, 3, 5, and 6 ( on the RS232 cables ) TR,
RX, CTS, CTR, if memory serves.
In any case, on your standard 8 wire patch cable, pin 2 is transmit, pin 3
is receive. When communicating directly between two DCE or two DTE devices,
one can transmit only to the receive, and visa versa. Hence the crossover,
i.e. the transmit wire/pin being "crossed" to the receive wire/pin on the
other side.
I'm still a bit curious why sometimes your router to switch connection
requires a crossover. Normally this should not be the case.
Quick search on winfiles.com didn't turn up anything either. Where have all
the fun things gone?
Chuck
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
Leigh Anne Chisholm
Sent: Thursday, August 10, 2000 8:10 PM
To: Yee, Jason; Cisco@Groupstudy. Com
Subject: RE: cross or straight?
Let's look at things logically. When we connect two PC's together, we use a
cross-over cable. A cross-over cable logically connects the transmit pair
on one side, with the receive pair on the other side.
Now, if you were to connect those same two PC's together using a hub, the
hub would perform the transmit pair to receive pair connection process - you
would use two straight through cables (one connected to each PC, terminating
at the hub). Picture the hub port as having an "x" on the port, signifying
the transmit to cross-over process.
Now let's throw in something a little different. PC "A" is connected to hub
"A". PC "B" is connected to hub "B". Hub "A" and Hub "B" are connected
together. If both PC's were connected to their respective hubs with
straight-through cables (as they should be), what type of cable should
interconnect the two hubs? Draw yourself a diagram, and show the transmit
to receive switching processes at each stage. That should help you to
identify what type of cable to use between hubs, or between a hub and a
switch.
Now earlier I had to picture a hub port as having an "x" on the port - some
hubs and switches do in fact have an "x" marked on one or more ports. After
you understand when you require a cross-over cable, and when you require a
straight through, I'll explain the significance of the "x" on the port.
-- Leigh Anne
> -----Original Message-----
> From: Yee, Jason [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 10, 2000 8:57 PM
> To: '[EMAIL PROTECTED]'
> Subject: RE: cross or straight?
>
>
> I know that's the case but I wish to know the details you see
>
> thanks anyway
>
> if you can input more all the best
>
>
> Jason
>
> -----Original Message-----
> From: Leigh Anne Chisholm [mailto:[EMAIL PROTECTED]]
> Sent: Friday, August 11, 2000 10:48 AM
> To: Jason; [EMAIL PROTECTED]
> Subject: RE: cross or straight?
>
>
> Because...
>
> sometimes cross wires work, sometimes they don't. If they don't, then we
> need straight.
>
> And sometimes straight work, sometimes they don't. And then we
> need cross.
>
> But seriously, think about transmit and receive...
>
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> > Jason
> > Sent: Thursday, August 10, 2000 8:32 PM
> > To: [EMAIL PROTECTED]
> > Subject: cross or straight?
> >
> >
> > hi Anyone
> >
> > knows why sometimes we need straight and sometimes we use cross wire?
> >
> > sometimes switch to route we use cross and sometimes we use straight?
> >
> >
> > Any input will be greatly appreciated
> >
> > thanks
> >
> > Jason
> >
> >
> > ___________________________________
> > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> > FAQ, list archives, and subscription info: http://www.groupstudy.com
> > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
>
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