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.

I purchased this item for the sole purpose of retrofitting an Allen-Bradley MicroLogix 1400 to a machine still running on a 1980’s-era SLC 150.(Please…Don’t ask.)I basically needed to pull the program from the venerable 150 and transliterate the instructions into RSLogix for the 1400.I won’t bore you with the “joy” that is reverse-engineering a program line by painstaking line in a utility written for DOS.XDWhat I WILL tell you is that when configured properly in Windows Device Manager (i.e. assigned to COM1), the ancient PCIS software recognized the USA-19HS as a “real” RS-232 port which worked flawlessly at 19.2k baud in DOSBox, which was a small miracle in and of itself considering this particular PLC was so overdue for retirement that it “forgot” its program and faulted the very minute I de-energized the machine and performed LOTO.-.-I am also pleased to report that this particular USB to Serial converter works equally well with the MicroLogix 1400 and autoconfigures like a dream in RSLinx, although the A-B software/hardware limits practical speeds to 19.2k baud maximum.

The adapter itself is a remarkably lightweight piece of kit that you can easily slip into your laptop bag or pocket, as the PCB is housed in a translucent smoke-colored plastic that I wish was a little sturdier, but I’ll elaborate more on that later.The tapered side of the adapter has a snug-fitting USB B female connector which is more than adequate to hold the weight of the adapter itself, while the wider side contains the obligatory 9-pin Male RS-232 port with securely attached posts that I’ve yet to see come unscrewed in use.The clamshell package also comes with a software installation disk that you MUST run before plugging the USA-19HS into your laptop or PC in addition to a USB A to B cord of decent length and quality.However, I highly recommend that you get a coiled one instead (which, thankfully, Tripp-Lite also makes) lest you do what I did and accidentally stretch the cord to the point where the adapter pulls free, falls onto a concrete floor, and bounces/skitters quite a few feet away.x.xI can’t imagine this adapter ever breaking in “normal” use, but in an industrial application, you definitely want to be more careful with it.Despite the housing only being held together by wishful thinking after my admittedly careless handling (as a few tabs broke off inside the unit), it continued to work without any issues whatsoever.I’d say this was pretty impressive for an inexpensive piece of equipment that you’d not expect to survive such treatment.

The bright side to this story is that Tripp-Lite’s customer service was extremely helpful and accommodating when I called them to explain what had happened, and that I was using it for my job.Without any further questions much less hassle, they told me they’d just send a new unit directly to my workplace free of charge.Although they did caution me not to make a habit of submitting future warranty claims, I’m still very pleased that they stand by their products so much for commercial/industrial users.

Were it not for the plastic Tripp-Lite uses in the unit’s housing, I’d have given the USA-19HS five stars easily.Granted, the aforementioned 9300-USBS is much more ruggedized and thus better suited for industrial use, but it also uses an FTDI chipset rather than the Texas Instruments chipset of the former and comes with a far more hefty price tag to boot.All said and done, I’d rather save my money and just treat the $25 Keyspan with kid gloves.Durability gripes aside, it’s an indispensible tool that shall always reside in my laptop bag along with my 1747-UIC and the 1745-PCC convertor that I’ll (hopefully) never need again.XD