With the new year came some new toys, but I still have the same old Doctor's Bag, so I needed to find out what needed to stay, and what could be combined or made smaller.
One of the relatively large things were a couple of DB25 Loopback modules, from Cyclades (one included with each server, so I have a bunch). To use this useful tool, I also have a collection of DB25 adapters for a few of the console servers I often work with.
I'd tried using some simple loopback plugs...just short wires into an RJ45 plug (sometimes called an 'ice cube') like the one you also get with a new Cyclades console server...but these get lost in places, sometimes even lost in console server ports if bigger gear is mounted above and below the console server, so I gave up on them.
My next attempt was a 'pigtail'...a 4"-6" section of cable into the 'ice cube'. This was a 'flag', to help me find it sticking out of the console server, but I still had the trouble getting these out of console servers which had been mounted in tight corners.
All the while, I still needed a way to check the signal at the other end of the cable. My real concern was usually "do I have good connectivity up to the back of the machine?", and this required a loopback at the device in question, so I started packing the loopback modules.
I'd thought about taking an RJ45 socket out of a patch-panel, and looping wires around in that. It would be smaller and lighter, but how do I label them. I thought about using color, like the hood colors on the console server adapters. (As baby boomers get older, color coding lets one get by without reading glasses, at least some of the time.) I'd tried a variety of discarded sockets, with some success, but they all had flaws.
I finally stumbled on a part that I like for the purpose! Panduit's Minicom line of CAT-3 patch panel parts. You can get them in the common resistor color-code colors, they are compact, rugged, you can buy them in small quantites, and they have a flat spot you can use for labeling the jack. I'll try to get a couple pictures on Flickr, so I can link them here (and update my Doctor's Bag page). The only real modification to make is to round the sharp corners with some sandpaper, so they don't cause problems in the bag.