In the following configuration, notice that UPSCABLE and UPSTYPE are not configured as usb. However, when using the Keyspan USB-to-serial adapter, nf needed to be configured differently. This is because apcupsd will try all the known USB ports until it succeeds. Note that UPSCABLE and UPSTYPE are configured as usb and DEVICE is not defined at all. For a typical USB configuration, nf would be setup as follows. When using the Keyspan adapter, the only caveat is that communication with the UPS is configured as using a serial cable instead of a USB cable. I’m using apcupsd to monitor the UPS and control the server during a power outage. So before discovering and solving this problem, I setup the UPS with a Keyspan USA-19HS USB-to-serial adapter, which I thought would be an easy fix. Initially, I had communication problems as a result of purchasing the wrong IDC10-to-DB9 serial adapter. I did, however, own one of their proprietary serial cables, part number 940-0024C, so that’s how I set things up. Although this UPS is capable of USB communication, APC uses a RJ45 connector on the back of the unit, and I didn’t own one the correct cable. I’m in the process of building a server with Ubuntu 12.04, and I needed a serial connector to communicate with an APC Smart-UPS RT 1500VA RM. If you want to know more about how I discovered this and the differences, then continue reading. I had just such a need recently and discovered that there are two industry standard pinout conventions in use, the AT/Everex and the DTK/Intel. If you have a need for a serial port, then an IDC10-to-DB9 serial adapter might be required. With servers, however, the serial port is still in use, but sometimes it’s only available as an IDC COM header connector on the motherboard. But with USB being a much better protocol and easier to use, the serial port has just about disappeared from modern desktop computers. At one point, the RS-232 9-pin Serial Port used to be a common connector on the back of every computer.

Serial port pinout computer db9