Home networking odyssey: The first cut is the deepest

By Mike Azzara

Chapter 4

Aug. 30: Later this afternoon I attempted my first cat5 cable termination. To conquer my fear of screwing up, I took one of the many cables I had collected in a file drawer over the years and chopped off one of its end modules. If I destroyed this cable, you see, there was no real loss involved. I carefully stripped off a half-inch of the outer casing. This took a couple of tries to get right because the stripping blade on my crimping tool was imperfect and bit a little too deep. The eight colored wires were next on my worry list. The standard order in which the eight wires must be inserted into the module, or jack, for the cable to work has been the subject of much discussion. Two differing standards exist:  568A and 568B (See illustrations below). The Web page that taught me all this stuff assured me order didn't matter as long as both ends of the cable were consistent. I checked the intact end of the cable and determined it used 568A (the color codes are available on that Web page, which I printed and carried with me whenever I crimped a module or jack).

 

The Web instructions were also clear about sloppiness, specifically that any extra wire left untwisted after you crimp it into the end module will degrade performance. If you're sloppy enough, the wire may not even work (See photo on the right). Suffice to say, neatness really counts. So I sweated it out and in the end had a crimp with virtually no excess untwisted wire. At 4:59 p.m. I sent Strom the following e-mail: "Hey, I'm sending you this e-mail over an Ethernet cable with a connector that I crimped myself! (See photo below) It was so easy. Of course, I studied for this test for some hours. :-)"

 

At 5:09 p.m. I followed up with this message: "On the other hand, the throughput difference between my cable and the store-bought cable is MAJOR. Mine stinks. I should have tested the original, though, before I cut off the old end and put the new module on (this was my first practice cable). Sigh." Because I failed to test the original cable, I had no idea if the lower throughput was the result of my crimping job or whether the cable had been slow before that.

Mike's Home Networking Odyssey

1: The original home network mess

2: The great modem swap

3: Of scrimping and crimping

4: The first cut is the deepest

5: Mike's first punch down

6: Wiring the family club

7: Microsoft workgroup voodoo

8: From the frying pan to the freezer

9: The power of perseverance

My second cable worked much better. This time I tested the original cable before cutting off one of its modules, and the file I downloaded settled down to a rate of about 220 Kbps. After I cut it and attached my new module, it worked just as well, if not better: The file I downloaded settled down to a rate of around 230 Kbps to 240 Kbps. Interestingly, when I checked the original connector to determine which standard the cable used—568A or B—I discovered it used neither but instead had its own variation. I matched that variation, and it worked fine. (Note: All the file download rates I quote here and below are, for comparability, from the same, rather slow, Web server. Since then I've experienced more than 2-Mbps download speeds!)