(Please see my update at the end of this review before considering the purchase of this adapter) I've been using the Keyspan USA-19HS for years. The first one was purchased after reading recommendations from several control system experts, and I haven't been disappointed. Rockwell Automation sells their own version of a USB serial port adapter (PN 9300-USBS), but it's about $130. Don't bother. The Keyspan is inexpensive and has proven to be 100% compatible with everything I've needed to connect to via a serial cable. I've used it with laptops and desktops running Windows 98SE, Windows XP and Windows 7. I've used it on SLC 5/xx series processors, ControlLogix 5000 processors, Siemens/TI 505 series processors, Keyence laser measurement equipment, modems, serial printers, barcode scanners, Reliance and Rockwell/Allen-Bradley drives, and just about everything else. Never a problem. It works with straight serial cables, null modem cables, and every type of serial adapter I've thrown at it. The Keyspan USA-19HS is the cheapest piece of control system communication hardware that I own, and it's probably the most-used. It has never let me down. Since I first started using the Keyspan adapter, I've bought over a dozen more for service techs, co-workers and even a couple of bosses. The Keyspan is extremely configurable, fast, reliable, durable and easy to use. The Keyspan adapter comes with a driver CD and a USB cable and takes just a few minutes to set up. I keep one in my laptop bag at all times. UPDATE 4/5/12: it appears that Tripp-Lite has made a few changes since they took over the Keyspan line. Among the changes was a decision to use a cheaper USB socket. From the outside, it looks almost the same. The only notable difference is a lack of molded numbers (1, 2, 3 and 4) on the end of the plastic tab in the middle of the port. Unfortunately, the cheaper USB socket doesn't retain the cable connector as well as the older ones did. The weaker spring conductors allow the cable to be pulled most of the way out of the socket, resulting in a lost connection and possibly a BSOD (blue screen of death). I took a couple of the older Keyspan adapters (no Tripp-Lite logo on the housing) and a couple of the newer Keyspan adapters (with the Tripp-Lite logo on the housing), opened the housings and compared them. The differences I saw between old and new were minor: notably a different PCB manufacturer's logo and a couple of chips that had changed brands. And the USB type B port. The old has a partial back shell (you can see the white plastic on the back of the port), while the new has a full back shell (can't see the plastic in back). The few cents that Tripp-Lite saved by using a cheaper socket isn't worth it. Whereas the old Keyspans would easily support the weight of the adapter + a 10 ft. coiled-up serial cable, the new Keyspans cannot. The new ones can't support the weight and allow the USB cable to pull partway out of the port. I tested 3 of the new Keyspan adapters and they all performed the same: almost no load-bearing capability at all. Since the adapters still work fine except for the USB port, I simply desoldered the cheap-o port from each of the new adapters and replaced it with an FCI port (FCI PN 61729-1011BLF -- 54 cents each). No more problems. Most users probably won't be able replace the port, so a quick (if not awkward and/or ugly) fix is to either glue the USB cable into the port or use tape or a heavy rubber band to retain the cable. Tripp-Lite, shame on you for ruining a perfectly good adapter to save a few pennies. I have reduced the adapter's 5 star rating to 2 stars based on the poor quality of the new USB port. Like the old Baskin-Robbins saying goes, "There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper, and the people who consider price alone are that man's lawful prey." UPDATE 10/11/12: A coworker bought a half dozen new Keyspan USA-19HS adapters today, so I wasted no time in testing them out to see if the USB port problem was fixed. I tested all 6 of the adapters and was happy to see that none suffered from loose USB ports. The ports don't have any numbers (1, 2, 3 and 4) molded on the end of the plastic tab in the middle of the port, so I'm guessing they're not anything special, but they seem to hold onto the USB cable quite well. I only hope Tripp-Lite has learned a lesson about trusting others to adhere to high quality standards based on faith alone. I have updated the adapter's rating from 2 stars to 4 stars based on seeing and testing this batch of adapters.
