Well, a short while ago, we got a APC Back-UPS pro 1400. Now, when Simon bought his smaller Back-UPS PRO 420, a serial interface cable was included, and he can use this to get various status information out of the UPS. The Backups-PRO 1000 and 1400 don't, it seems, supply most of this information, which is fair enough. However, they also don't come with a cable. So, I first set about attempting to buy a cable, although APC refused to tell me which cable(s) would actually be suitable; and they don't seem to sell the 940-0095A (as suggested here). to cut a potentially long story short, here is a page which, amongst other things, contains a circuit diagram of the pertinent 940-0095A cable. And I've built one.
Shall we just say that trying to cram so many component legs into one solder connector, and doing the soldering while being unable to find things (partly as a result of the incompetence of Rossiters Removals) was "phun". And, much to my surprise, it works... Well, appears to work.
The gray cable is just standard cat5, with unneeded wires cut back. Chosen mainly because we already had it. The DB9 plug, socket, and plastic hoods are all available from Maplin. Order codes RK60Q, RK61R, and FP27E might be worth looking at. Also used were 2 M47K resistors, 2 M4K7 resistors, 1 QL80B diode, and the transistor is a QR42V. Component leads were trimmed to allow everything to fit. The cut component leads were used for the connections needed. These aren't insulated, so were carefully bent such that unwelcome shorts are unlikely to develop. However, it might become necessary to pot the assembly with hot-melt glue, or epoxy or similar.
Please note, if you're building a cable like this, you should double check everything is correct. A finer soldering iron would probably be an advantage... I also pre-assembled the components, to be sure everything fitted, which also indicated that not everything fitted in the connector for pin 6, although the construction allowed a little flexibility (with the aid of a little widening with a screwdriver). Note too that I don't know how well this cable will work long-term; while the components appear to be suitable they may fail in time. It seems quite depressing that people have to keep saying this, I'm not responsible for your actions/mistakes/misinterpretations, or their consequences. This page is for posterity purposes only; I'm not building cables for anyone other than myself. I have, however, uploaded 4 close-up shots of the cable, taken after it was assembled, but before it was soldered: 1, 2, 3, 4.
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