KEYSPAN USA-19HS USB to Serial adapter:Summary: I had a device that came with a USB-Serial adapter from FTDI Chip that only worked intermittently, was poorly documented, and the vendor ignored my e-mail. The KEYSPAN USA-19HS worked flawlessly, is well documented, and comes with a powerful utility (which I did not need).Details: Recently I acquired a "Duplimate Mark IV bis" duplicate bridge card dealer. It uses a serial connection to the host Windows computer. I'm using an IBM Thinkpad T40 running Windows XP SP2. The computer has no serial ports, but the Duplimate came with an adapter, as well as a serial cable. That adapter has a captive USP cable, and a DB9-F connector for the serial device (unusually, with screws - no independent serial cable needed). The adapter was identified only by manufacturer, FTDI Chip. It came with a mini-CD, which I explored and used to print out the manual. I eventually deduced that the adapter was an HL-340, which I found stamped on the DB9 connector and as the name of a folder on the mini-CD, but not in the manual. I installed a driver in that folder, and got the dealer to work - kind of. It would actually deal a hand only about half the time, otherwise taking several seconds to report a communications error. By the time I had hit Ctrl-A to restart dealing for the fifth time on a deal, I was wondering what I would do if it refused to deal. FTDI Chip has a web site, and I downloaded a driver from there - no use. I did perform a successful reinstall without using the HL-340 folder directly, with no change in results. A detailed e-mail to FTDI chip produced no response. If you ever have a chance to buy something from FTDI Chip - DON'T! Two days ago, I ordered the KEYSPAN USA-19HS from Amazon for just under $32, with free shipping. It arrived today, and I put it through its paces. It comes with a full-size CD. First, I removed the old driver. When I installed the Keyspan software, which must be done with the adapter disconnected, the driver went right in. (I also took the time to register the product.) A Keyspan USB Serial Adapter folder appeared on my Programs menu, and it contains a powerful and potentially useful Keyspan Serial Assistant - as well as the manual in HTML and PDF. Don't read the manual on CD - it's slow - wait to read it on your computer. The manual is excellent, tho you may not need it. The adapter has a short detachable USB cable, which is probably fine for most applications; but if you need a longer one, you can substitute. Using the serial assistant or Start-Control Panel-System-Hardware-Ports confirmed that the newly connected serial port was COM3. The DB9-M connector has nuts for the screws on a typical serial cable, so it would not mate with the Duplimate, which also has nuts. No problem, I had the serial cable that came with the Duplimate. While using the extra cable is not as convenient, I judge this to be the correct implementation, because it will mate with captive or specialized serial cables. Because my WinDup software was already configured for COM3, I was able to fire it up and start dealing immediately. No more communications errors, no more waiting to hit Ctrl-A if the machine did not start dealing immediately. It always started dealing as soon as I inserted the next board.

My go-to DB9 RS232-USB serial adapter.A bit clunky on one end, but this works great, and I always use it to determine if other smaller/cheaper versions are working.

Installed the configuration software, plugged it in, and it worked immediately. I am using it with WinXP Service Pack 2, and it communicates great with a complex serial interface to an unusual piece of electronics I have, so its very compatible with "real" serial ports, unlike some other adapters I have tried that seem to only work with modems or PDA docks. The adapter as shipped is actually a small 1"x1.5"x3" box connected to your computer with a 3' USB cable that can be unplugged from it. It has a green LED on top to tell you when it is properly configured as well as when a program has opened that serial port and when it is passing data. Very functional and easy to use; the configuration software even includes tests to make sure the device is recognized and is properly communicating with your computer. The configuration software also ensures that the same COM port is assigned to the device, no matter which USB port on your computer you plug it into each time, unlike previous adapters I've had which created a different COM port each time you plugged the device into a different USB port (very annoying); the driver also has an option to behave like those other drivers, but most people will probably want to always have it act like the same COM port, the default.

Effortless connection for my old Serial/Parallel port vinyl plotter. I have a 2000 model year Vinyl Express 32" vinyl cutter that that had only a serial port connection. With this adapter, I was able to upgrade my machine to USB connection on a Windows 10 laptop. It was very simple once I updated my old Win 2000 software, the Vinyl Express software and then added this port converter so they could talk. I didn't need anything more, even the CD was included with a driver that worked perfectly. Don't give up on old serial port equipment if it still works well. This is a reliable and inexpensive solution. The connector takes a standard USB cable connection just like your printer has. A 3' cable is included but since the adapter is independent of the cable, not molded together into one piece, you can use any standard USB cable to achieve the length you need. Highly Recommend!

I have used several different cheaper adapters that use the common Prolific chip and drivers. All of them have had spotty results, compatibility issues with various versions of Windows and MacOS. However the Keyspan USA-19HS has always worked perfectly for me, requiring no driver installation on Windows XP, 7, 8 and 8.1. Even though this unit is a little more expensive that the others, I highly recommend it.One of the cheaper adapters I purchased would only work with drivers that were designed for Windows Vista, and even though I was able to make it work by installing that driver on my Win 7 box, as soon as I unplugged it and plugged it in again, the Vista driver was automatically over-written by the Win 7 driver, and the adapter stopped working.One serial device I own (a security alarm controller) came with the recommendation to use this Keyspan adapter for USB connections, and I have found that this is completely true. No other adapter works with that device.An additional benefit of the Keyspan device is that the USB cable unplugs from the adapter itself - using a standard USB cable that can be obtained in many different lengths. This can be a big help in managing cabling between the adapter and the computer.

I’m using this to do connect with medical devices for maintenance. I’ve tried many other USB to serial adapters but I’ve had many issues. This is the only USB to serial adapter that always works

Este producto es bien conocido por mi, lo uso constantemente con impresoras POS y es muy recomendable.El precio es muy aceptable y la entrega bastante rapida.Muy Recomendable.

After purchasing a few from eBay that didn’t work or failed first time… this one is robust and worked first time …. Great purchase.

Prodotto di qualità superiore alla media. Disponibile anche un piccolo software per gestire la periferica e testare la comuncazione.Arrivato in tempi brevissimi!

Keyspan USB to serial adapter is just the best in the market. It works immediately 100% compatible with windows. I got also one I used with my mac for years. Strongly recommended!