Tech Laptop with DB9

Hi all,

DB9 ports seem to be a nearly extinct feature on laptops. Any suggestions on a cheap laptop for use in field support (with an onboard DB9)?


Get a cheap usb--serial converter. Check amazon for trend usb rs-232 db9 serial converter, tu-s9. Then you can just use whatever laptop.


If you are able to carry a USB cable I've actually found that these work PERFECTLY:

I've never had an issue, I currently have an OOB console server set up with the 4 head version of this and haven't had an issue. They're rock solid.

You might be able to pick up something like an old Dell Latitute D800 series pretty cheaply. Built-in RS232 serial ports are very tough to find on current laptops, however USB serial drivers have come a long way in the last several years, depending on your OS.


Might be easier to get an "Aten UC232A" converter to do USB<>DB9, you
are right that DB9 directly on laptops is a dying breed. Do you have a
specific application that would prohibit the use of USB?

Kind regards,


It's purely for convenience and forgetfulness.

You can look at older Dell Latitudes such as D620 or any Prolific based
USB-to-Serial adapter (If running those on Windows, you can set the driver
so that it will report the same COM port even if it's plugged in different
USB ports).

ftdi chipsets work on both mac and windows devices.

If USB is banned, ask about expansion cards. The HP 650 G1 has a serial port, but it's not cheap.

We recently bought some HP 6570b laptops. They come standard with a DB9 in the back.

I have found Air Console to be amazing:

I have one that comes with me in my bag everywhere.

I also have purchased a couple of their 1.8M USB to Cisco Rollover Cables which include the USB to Serial converter in the USB Plug. The cable can be adapted to serial and null modem with the end adapters (may not work in every situation)

The FDDI chip in these cables has strong driver availability across all OS’s and is also installed by default in some OS’s (including OS X - my personal preference for direct interaction machine)

This way as long as you have USB ports and Wifi you have an awesome tool set. The Air Console can even bridge traffic for monitoring / wireshark over Wifi (obvious bandwidth limitations) so I really enjoy having it with me.


Alexander Neilson
Neilson Productions Limited
021 329 681
022 456 2326

You can pick up an old toughbook on eBay that have serial ports for reasonable prices. Put in flash disk and run linux for a reasonable experience. But for the height of convenience you cant go past an Air Console. Nothing beats being able to plug it in deep inside a rack and then walk back to a comfortable seat to work. Beats the cold data center floor any day!


/* Matt Perkins
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I've seen some cheap RS-232 converters fail with some devices. I was
last bitten by one that just refused to work with Cisco Aironet APs 2600.

I can't say if it was the device or the driver. I never knew what the
problem ultimately was. Using a different model or brand worked.

Just to have the precaution.


I had a cheap one. Worked great but never worked on Windows 7

This is the one I recommend.

Anecodotally, I recommend against Prolific-based solutions. While doing some embedded dev work, I quite unintentionally found a specific data pattern that would reliably get corrupted by the Prolific cable I had. After several hours of debugging my software, finally resorting to a 'scope to verify that the data on the line was correct, I chucked it in the trash after I found that it worked fine with my 1st-party FTDI cable. Probably should have kept it and tried to isolate a minimal test case, but meh.

1st party FTDI cables can be had with bare wire ends on them. With a little effort, you can crimp an 8P8C directly on and have yourself a Cisco-style cable that's very reliable and includes traffic indicator lights in the USB molded housing. I think you can also get them pre-wired to DE9 connectors. They've got RS-485 and RS-422 options, too. I buy them from Digi-Key - not the cheapest place by any means, but you know for sure that they're real.

I've had good luck with FTDI on all OSes. No drivers needed on (modern) Linux, and the drivers are easy to work with on all versions of Windows that I've used with them (XP, 7). Dunno about MacOSX, but I think there's at least options.

YMMV, of course. FTDI got in some hot water recently by intentionally bricking 3rd party clones of their stuff in a Windows driver update.

ftdi chipsets work on both mac and windows devices.

I'd be careful with FTDI chipsets, you want to make sure you get the real chip. If they decide to move forward with bricking counterfeit chips, you'll be wasting your $$.


You mean like they did with the last driver update pushed via Windows

The bonus about the adapter that I linked is that they use legit chips.

I went through the FTDI driver update without a problem.

As long as it's FTDI and not "FTDI"...

- Matt

Cable ties. They're my forget-me-not.

- Matt