>I have a Nortel Annex terminal server, of which I want to connect an
>E280R and a StorEdge 3310.
>The Annex's 8 serial ports are all RJ45.
>The E280R has a 25-pin serial port.
>The 3310s has a 9-pin serial port.
If you check the system handbook for the E280R, you will find there
is a reference in the Server's owners guide for the pins and signals
on the serial ports along with a diagram. If you aren't fluent in
serial signals and have no interest in learning, then a competent
supplier should be able to help you construct the cabling you need.
Usually, all it takes is a diagram of both sides.
If you want to learn more, the Sun System handbook has the basic info.
Celeste Stokely's site (www.stokely.com) is the definitive Solaris
serial port site. It contains just about all the Sparc serial port
diagrams but examples of serial null modem and serial null terminal
cables (the difference there being the presence or absence of the DSR
DTR DCD signals).
Quote:>I have been asking around in the electronics shop here in Sydney (
>Tandys,* Smith, Reids behind the QVB ),
>but when I say serial null cable, they dont seem to completely
>understand what I mean.
>( Except for one guy who understood what I meant, but said they are out
>of stock ).
Well it doesn't help that your local "electronics" outlets don't seem
to have properly skilled employees, but this is usually the rule not
the exception. That's probably why there are so many internet
suppliers of cables, including Black Box, which, while pricey, can
either provide or build just about any cables you would need.
Vendor sometimes provide these cables. Sun only provides the adaptors
for RJ45 to DB25 or DB9 to be used with a shielded cat 5 cable.
>They ask, "oh, a crossover" ... but IIRC, a crossover <> null serial cable.
>Then there is another cable called a rollover.
>So what's the diff between a null cable, a crossover, and a rollover ?
Here's a diagram of a null modem cable 25pin to 25pin from the Stokely
1 GND ---------- 1 GND
2 TD ---------- 3 RD
3 RD ---------- 2 TD
4 RTS ---------- 5 CTS
5 CTS ---------- 4 RTS
7 GND ---------- 7 GND
6 DSR ---+
+------ 20 DTR
8 DCD ---+
+--- 6 DSR
20 DTR ------+
+--- 8 DCD
I've heard the term "crossover" used interchangeably with "null modem"
but I don't think it's correct.
Looks like we aren't the only ones confused by these terms, as this
discussion on the Ars Technica forum shows:
I've seen diagrams of a "rollover" cable and it basically looks like
1 > 8
2 > 7
3 > 6
4 > 5
5 > 4
6 > 3
7 > 2
8 > 1
Here's an example from the Cisco website:
Good luck and happy cabling!