I bought this USB to TTL cable: https://www.amazon.co.uk/dp/B01DC0S13M

Since it apparently uses the PL-2303HX chip, I downloaded the driver for Windows here: http://prolificusa.com/portfolio/pl2303hx-rev-d-usb-to-serial-bridge-controller/

After that, I connected the USB to the PC and the TTL pins to a single board computer. Unfortunately, my PC hasn't detected the cable, because Device Manager doesn't list a COM port for it.

Is there a way to check if the cable is faulty? I don't have any other USB to TTL cable, so it could be something besides the cable.


closed as off-topic by Olin Lathrop, Daniel Grillo, Bence Kaulics, PeterJ, placeholder Jun 8 '16 at 13:29

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the use of electronic devices are off-topic as this site is intended specifically for questions on electronics design." – Olin Lathrop, Daniel Grillo, Bence Kaulics, PeterJ, placeholder
If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ The troubleshooting of electronics makes for excellent discussion and may contribute to driving better requirements for designs. An argument could be made that this should be opened for discussion. If the community is going to shutdown this discussion, it could be gracious by moving it to the appropriate venue... \$\endgroup\$ – gatorback Mar 14 '17 at 0:47
  • \$\begingroup\$ If using Windows: ensure you are using the Prolific Driver V3.3.2.102 dated 9/24/2008 and test it with Termite. If Ubuntu then driver is automagic and test with Cutecomm \$\endgroup\$ – gatorback Mar 14 '17 at 0:53

You may have bought a board with a counterfeit PL-2303

If so, you will have to try to get a driver from Wingoneer. They probably don't supply one, however. They probably depend on the (older) Prolific driver that didn't block counterfeit devices.

This site has some info on how to tell if you have a fake PL-2303

Basically: Check the device manager. If the USB-Serial converter has an error and a code 10 then it is fake. You might be able to dig up and use an older Prolific driver.

The better choice would be to buy a better converter with a real Prolific chip.
The knock-offs tend to be pretty lousy and will drive you nuts - they work most of the time, except when they don't and then you don't know why your communications drop out.
That's pretty bad if you are developing the device on the far side of the converter. You don't know if it is your error or the converter's error.

  • \$\begingroup\$ The converter doesn't even show up on Device Manager. Also, connecting the USB doesn't make a notification sound. Could it be an eletrical issue? \$\endgroup\$ – someguy Jun 8 '16 at 11:09
  • \$\begingroup\$ If it doesn't show up at all, it could be completely broken. Send it back and ask for a new one. If that doesn't work, then send it back and buy a different model (preferrably from a different manufacturer.) \$\endgroup\$ – JRE Jun 8 '16 at 11:11
  • \$\begingroup\$ Lost my faith, so I'll buy one from Adafruit. \$\endgroup\$ – someguy Jun 8 '16 at 11:14
  • \$\begingroup\$ Sounds like a plan to me. Sometimes cheaper ain't. \$\endgroup\$ – JRE Jun 8 '16 at 11:15

I have 2 exactly same cables which I have bought here, both work like a charm. Of course, that doesn't prove anything, but fake cables usually come from el'cheapo manufacturers who don't bother to replicate the exterior looks so precisely.

I wouldn't be surprised if your cable was not counterfeit, but simply defective, especially if it doesn't show up in device manager at all (does it?). Either way, time to open a dispute with the seller.

  • 1
    \$\begingroup\$ I think you're right -- it's just defective -- but are you sure that's the exact same cable? I'll still get one from a better known manufacturer, though. Only reason I chose this was because of free next day delivery, but I don't need that anymore as a collegue lent me one. \$\endgroup\$ – someguy Jun 8 '16 at 15:43
  • \$\begingroup\$ Well, if you can buy a cable from a better supplier, by all means go ahead. Better be safe than sorry. \$\endgroup\$ – Dmitry Grigoryev Jun 8 '16 at 16:06

The world is awash with fake USB->Serial products, both FTDI and Prolific, and they're both engaged in an arms-race with the fakers to stop them camping-out on their (expensively written) drivers.

I would throw it away and buy one from a reputable source.


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