Why did I create a DB9 null modem cable? Well, the electronic stores in my area only had a DB25 null modem cable, so I tried that in conjunction with DB9 adaptors on each end, but that failed to work. So the next recommendation was to make my own. It's really not that difficult, nor very expensive to buy the necessary accessories, including the iron. Nothing like getting your hands dirty (and burnt in this case) to work up a good sweat. Now that I have soldering under my belt, I think I might build my own 1900 switch next. Got the schematics, anyone?
There are basically two types of connectors solder type and crimp type. The crimp type typically come with pins that you insert the wire (often part of it is bare) then using a crimping tool (one made specifically for the type of pin you are crimping) you cause the pin to compress the wire. When done right the pressure on the pin will create enough heat that the pin and wire actually melt together. Creating both a strong mechanical and excellent electrical connection.
Beware for DB9, DB15, DB25 etc. connectors sold at radio shack come with pins that should not be crimped with the radio shack crimping tool. It ruins the pins. I have found instructions in more than one network-cabling book that provides wrong instructions. The barrel on the pin should never be crimped. The shorter flange behind the barrel should crimp bare wire. The longer flange at the back end of the pin should crimp insulation for strain relief. Techni-Tool sells a contact crimp tool part number 104ST312 that works well. It’s also expensive just as all good crimp tools are.
Do not confuse this with CAT5e and CAT6 cable and RJ-45 connectors they are another story all together. See the post on RJ-45 Crimper advice for excellent advice pictures included.