Insert Wire A into Slot B (specialty cables and adapters)

The other title for this article could be "Pocket Notes (you really CAN take it with you)". Here's how I 'remember' how to wire a serial crossover cable when I'm in a data center, without easy web access.

I used to carry a small pocket notebook with notes and adapter diagrams, but those got worn and ratty and dog-eared. So I kept them in a computer, printed the notes and drawings, and carried a small (5" x 8.5") binder. This way, I could mark-up the notes when I was away from the computer, and make changes on the computer, and print more 'clean' pages. It was also easy to give a page away, since I knew I could easily replace it. Eventually, the binder got bigger, thicker, and heavier, until I finally started carrying the computer around.

Now, ten years later, I keep my console information pages on the web, but I also keep critical notes on my Treo (Palm OS device). But the OS isn't important! If you have a pocket/palmtop computer, you can use the memo functions to carry useful cable info in the note files.

ASCII art isn't easy, and it isn't pretty unless you are using a mono-spaced font. But recording the wiring for specialty cables is easy. In an earlier posting, I described how to determine the wiring for specialty cables. And most of us could easily spout off the wiring sequence for an AT&T 468B-wired CAT-5 cable, right? So, you start with that color sequence on one end...but what colors do you need on the other end? THIS is easily described with text, and proportional fonts do not get in the way.

I usually show the cable, wired from both ends, since I can use a simple RJ-45 cable continuity tester...but, I add the Cat-5 color code in between the pin numbers. I use the AT&T 468B sequence on the first end, since it's a good visual starting place. Then, I show the sequence on the 'other' end, with the resulting color sequence. It's this other sequence that it hard to translate in my mind, so I keep a 'note' that won't get dog-eared in my phone, since it's almost always going to be with me.

Here's an example of a crossover cable between Cyclades ACS Console Servers;

Cyclades crossover
one end...
1 whi-orn 5
2 orn-whi 8
3 whi-grn 6
4 blu-whi 4
5 whi-blu 1
6 grn-whi 3
7 whi-brn 7
8 brn-whi 2

other end...
1 whi-blu 5
2 brn-whi 8
3 grn-whi 6
4 blu-whi 4
5 whi-orn 1
6 whi-grn 3
7 whi-brn 7
8 orn-whi 2

Using the PalmOS memopad feature, I have note files for a variety of console servers. It's easy to combine wiring notes (crossover, loopback, signal inputs/outputs) for a single vendor into a separate file, for quick reference. You should be able to do something similar with other PalmTop devices.

I do still keep post-its handy at a few sites, with the "other end" wiring sequence, in case the memos aren't available. (The battery died, or I can't take a camera-phone into certain data centers...) When they start to get worn, I make new ones, using the records on my phone, or my web pages.

I hope this note is helpful to some of you. I know that it saves me a LOT of time.