5 Dec
2004
5 Dec
'04
8:48 a.m.
On Sun, 5 Dec 2004 13:01:29 -0500, Pat wrote:
On Sunday 05 December 2004 06:43, Pete Turnbull wrote:
If you made something like this, would the RJ-45 end plug into one of
the serial adaptors that I got from the back of a rackmount US
Robotics modem box? It's one of those plugs that adapts from RJ-45
jack to a DB-25 male plug.
If so, it would be great to get one of those. I'd do it myself, but I
literally have to look across a room completely stuffed with boxes of
junk to see my electronics bench. I really _really_ need to clean
things up.
I'm way out of it as far as serial interfaces and interface standards,
cable pinouts, etc. I null-modem into Sun boxes to install Solaris
and NetBSD over a serial console, and talk to my HP 95LX over a little
serial cable, but it's been ages since I tackled it much further. But
in the last month I've acquired two serial-console only machines.
(the MicroVAX, and an Altos 586 Xenix box (8086 Xenix in 512K of
RAM)). I'm so out of it as far as serial goes that I struggled for
half a day with the serial interface to the Altos box before I
realized 'hey, I should NOT be using a Null-modem cable to connect a
Linux box running Minicom to the Altos console. This is the REAL
THING, not terminal-to-terminal.' Could be it's time to design and
build up a 'serial switchbox/crossbar/multiplexer.' That would be a
cool app for a mid-sized PIC controller and some of those 6402s I have
lying around. Hmmm... A 'serial hub' to connect it all together...
I'm interested in one of those cables, Pat. To accelerate my getting
that MicroVAX online. I located a SCSI CDROM for it yesterday from my
hoard that has jumpers on the back labeled 'parity' and 'block size'
so I think it's all coming together.
Scott
Better than hacking RJ45s would be to hack RJ11
(6P/6C) plugs.
They're very common, about a quarter of the price of MMJs, and there
are low-cost crimp tools available.
Agreed, the only difference between an RJ12/RJ11 and MMJ is the tab
location, which can be easily sliced off (though that usually makes for
a loose fitting connector).
For anyone in the UK who needs *a few*, I believe
I still have a box
of adapter cables for Emulex terminal servers. These are short
(about 8-10 inches) flat cables with an MMJ on one end and an RJ45 on
the other. You can have a few for the cost of postage.
And if anyone in the US wants one, I can do up to, say, 25ft MMJ->MMJ or
MMJ->RJ(12/45) cables for $5 + shipping. I had a few takers last time
I did this, and they seemed to be happy with my handiwork. : )