According to Casper H.S. Dik <Casper.Dik@Sun.COM>:
> dnichols@d-and-d.com (DoN. Nichols) writes:
>
> >According to BertieBigBollox@gmail.com <BertieBigBollox@gmail.com>:
> >> OK. So let me get this right....

[ ... ]

> >> DB25 plugged into Serial A on sun machine.
> >> DB9 plugged into serial port of PC.
> >> RJ45 cable connecting the two. (straight thru or crossover ???)
>
> > Hmm ... do you have any idea how the pins of the connectors are
> >mapped to the RJ-45 pins? I'm sure that I have at least three or four
> >versions floating around here. It all depends on who wired the
> >connectors and for what purpose.
>
> The only RJ45 on the Ultra-60 is ethernet; you'll need a cross cable
> unless the PC does auto MDI-X (i.e., does not care)

I was thinking that he was talking about RS-232 connector shells
with an RJ-45 in the back, and thus needing to be connected to another
one via an RJ-45 cable. His "connecting the two" appeared to refer to
the connectors plugged into the computers at each end.

These are things like what the Cisco routers user for a serial
port, and that the RSC card in my Sun Fire 280R uses for a serial port
(along with another RJ-45 for the RSC's own ethernet port, and an RJ-13
for a modem connection to dial up pagers and the sort. :-)

The RJ-45 backed connectors can be convenient when setting up
serial connections -- if you know what the pinout is doing, or if you
configured the connectors yourself.

The main thing to do is to come up with a standard which you can
keep to, with four connector styles:

DB-25 DCE
DB-25 DTE
DA-9 DCE
DA-9 DTE

and make sure that if you connect any two of them with a
straight-through RJ-45 cable you will get a proper connection. (Also,
make sure to have a system for marking DTE and DCE -- perhaps with
different shell colors, so you *know* what you have just grabbed. :-)

If he is talking about the ethernet connection between the two,
he is rather jumping the gun before he can talk to the computer on its
own via either keyboard/monitor or RS-232 port.

Enjoy,
DoN.
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