Tag Archives: hardware

Making an Ethernet Loopback Adapder

This post will be short (and sweet). Ethernet Loopback Adapters are little handy pieces of equipment that route the transmitting pins in an Ethernet jack back to the receiving pins in the same jack. This is good for testing link connectivity on an Ethernet card – if the adapter can establish a link with itself the hardware on the adapter is probably OK. In real life, this can save you hassle quickly testing ADSL modems, routers, switches, desktops and laptops without plugging the device into another jack to get the link light to come on.

This how-to will use an existing Ethernet cable which will be converted to a Loopback cable.  There are lots of guides and video online about creating such an adapter using an Ethernet jack and wires, but this requires having an uncrimped  Ethernet jack, some wires, and a crimper. In my case, a trip to the store to buy the components I already have at home on ready Ethernet cables seemed wasteful (most people will have a cable or two, or can buy a short cat 5 cable for under 2 dollars). I strongly recommend using a cable with a broken or missing jack – after all, we only need one Ethernet jack which is properly wired to a cat5 or higher cable.

1. Cut the cat5 cable a few ( 2 or 3 ) inches from the jack.

2. Strip about an inch from the shielding of the cat 5 cable, revealing 8 separately shielded color coded wires inside.

3. Strip about half an inch from the shielding on four wires: green-white, green, orange-white, and orange.

4. Twist the green-white and orange-white stripped ends together, connecting pin 1 to pin 3.

5. Twist the green and orange stripped ends together, connecting pin 2 to pin 6.

If you have some tape, you may want to cover the tips up. Otherwise, make sure the tips don’t touch each other. The end result will look like this:

twisted pairs on an Ethernet loopback adapter

twisted pairs on an Ethernet loopback adapter

You can test your new loopback adapter in any working Ethernet jack by plugging it in!

You can see the Port line is on for a wireless router with the loopback adapter plugged in:

Link light on with loopback adaper plugged in

Link light on with loopback adaper plugged in

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Virtual Appliance with Debian Squeeze and OpenWRT-XBurst Development Tools for Qi Hardware’s Ben Nanonote

This post is about a Virtual Appliance with Debian Squeeze and OpenWRT-XBurst Development Tools installed, which would allow immediately compiling OpenWRT packages for the Nanonote without going through the painful process of setting up the development environment yourself.

As a non-developer, I found a working development environment to be the single most confusing part of porting to the Nanonote, even more confusing than OpenWRT’s Makefiles. Granted, this could be my personal lack of talent or skill, but it left me thinking removing this “steppingstone” for some of the less experienced users might open more doors, faster, for beginning Nanonote enthusiasts. The instructions at http://en.qi-hardware.com/wiki/Building_OpenWRT_on_Debian_6 are great, but might slightly intimidate less experienced Linux users. They are also slightly daunting to follow if the need arises frequently (if reinstalling OS, royally screwed something up, or other scenarios I’m sure you ran into).

The easiest way to get around this I could come up with was creating a Virtual Appliance which contains the basics for compiling for the Nanonote, using the wiki instructions for Debian Squeeze. Such an appliance can be run in VirtualBox (free and open source) or VMWare Player (free as in beer), even on Windows hosts. The result is a single 2.4 GB file with a ready toolchain which is ready to “accept” package Makefiles and compile them. Debian was installed, the toolchain was compiled, the locales and paths were set. I gave it a quick test compiling Pem (and a load of Perl dependencies) and it seemed to work.

The Virtual Appliance is currently unimaginatively called “Debian Squeeze with OpenWRT-XBurst Development Tools 2011-08-27” and comes as a single .OVA file. See details below:

Instructions
1. Install VirtualBox.
2. Download Virtual Appliance .OVA file (links below)
3. In VirtualBox click on “Machine” > “Import” and select the .OVA file.

I’ve added a brief section under the Building on … Debian Squeeze wiki page.

Hope someone finds this helpful.

2011-08-27 Release:

Virtual Appliance Download Page on 1fichier.com:  http://4pp1qh.1fichier.com/en/
.OVA file MD5 sum:  3ad6e2aa9379336c10746a3062538d32
user:  build
password:  gongshow
root password:  gongshow
QR Image:

2011-02-23 Release:

Virtual Appliance Download Page on 1fichier.com:  http://0tqstz.1fichier.com/en/
.OVA file MD5 sum:  f9ebe1b0cfe63ae1aa584ddff7b222ed
user:  build
password:  gongshow
root password:  gongshow
QR Image:

https://i0.wp.com/www.1fichier.com/qr/0/0tqstz.png

— Ernest Kugel

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Filed under Ben Nanonote