Serial ports on devices are still used for many things, especially on network devices. However, most modern laptops no longer have serial (aka "COM") ports.

So what I'm curious about is: what is a good adapter, or chipset used in adapters, that people use?

Ideally it would simply be plug into a machine and Just Work(tm) without having to install any drivers. This way anyone on a sysadmin team could simply grab it and use it without having to find the software CD or going online to find drivers. Also, I guess it should Just Work(tm) on Windows XP & 7, Mac OS X (10.5?, 10.6), and preferably Linux (2.6+) as well.

From the serial end of things, connecting a light-blue Cisco cable to it should make things run for any RJ-45-type serial console found on a good portion of equipment nowadays. (Generally assuming 9600 8N1.)

Thanks for any info.

closed as off-topic by Joel Coel, EEAA, Ward, HBruijn, mdpc Jul 13 '15 at 21:02

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I've had a couple, and I've seen some that are pretty doofily made. Whatever you buy, make sure it's got a female USB port (USB-B port) on one end and a female serial (DB-9) on the other end. I've actually seen them where the USB<->serial device had a USB cord. Stupid.

The one I use most often is this keyspan: http://www.google.com/products/catalog?sourceid=chrome&q=keyspan+usb+serial&um=1&ie=UTF-8&cid=14565954588677202805&ei=MYiKS4ymLYyWtgefyZm9Dw&sa=X&oi=product_catalog_result&ct=result&resnum=3&ved=0CCAQ8wIwAg#ps-sellers

  • This is the same one I use. – Keith Stokes Feb 28 '10 at 15:33

I have had varying experience when it comes to usb-to-com adapters, but best so far is the one from Aten (UC232A). It has good support and generally works painlessly. You can find it at http://www.aten-usa.com/?support_df&Item=UC232A and they are pretty cheap.


If you're running an OS from the last 5-ish years then almost all the USB-Serial cables work without messing around with them (you might have to mess with the Com Port settings, depends on your OS and application).

I bought a $10 cable years ago, works with XP, Vista, Win7, and FreeBSD 7.0+ without installing drivers.


A Gigware one from radio shack has worked well for me for connecting to the console port of Cisco routers and various switches.

  • I've used one of these for a long time, but the last couple times I had to set it up on a new machine it was getting hard to find the drivers. – Joel Coel Jul 13 '15 at 1:31

I tend to use the cheapest ones I can get off ebay and assume a 5 percent crap rate. I throwaway the crap and am generally happy. I never use the driver I get with the adaptor. Most just work, if they don't I get the driver off the chip manufacturer's website (which is normally ftdi).The only problems I have are that they are never full voltage (keep the rs232 side under eight feet and you won't notice) and sometimes you will get a batch with identical serial numbers (which is only a problem if you don't have a way to differentiate them like path and need to keep straight different equipment plugged into a bunch of identical ones).