[Elecraft] Test serial-to-USB converter

[Don Wilhelm]

Jan,

The best way to test a USB to serial converter is by substitution with a 
known good one, or by substitution of a known good working serial device 
connected to the questionable converter cable.

Yes, a power surge or a lightning event can damage serial interfaces as 
well as USB interfaces.

Since your USB ports on the computer seem to work, borrow a known good 
USB to serial converter and try it out - preferably one with an FTDI 
chipset.

If you have any other devices that use a serial COM port interface, see 
if they work with your USB to serial adapter - if so, the adapter is 
probably OK, but remember that in the event of a power surge, multiple 
failures are possible even though in normal troubleshooting we assume 
only a single failure.

You can test the USB to serial converter with a 'scope and an RS-232 
breakout box, but you have to know the proper RS-232 levels to 
understand what is happening.  A null modem loopback cable can be 
helpful if you have to proper driving software application for that 
testing.  I did that during my years of PC modem testing, but that was 
more than 30 years ago and the software ran under DOS - not helpful now.

73,
Don W3FPR

On 7/18/2016 6:36 PM, Jan Ditzian wrote:
> I have a K3 that lost communication with my computer. It uses an 
> Elecraft serial-to-USB converter and cable.  This probably happened 
> during a known power surge.  I also lost communication to my MDS 
> rotor, which uses a built-in USB cable, which I believe may also be a 
> serial-to-USB arrangement.  I checked things out a bit, and I can tell 
> that my USB ports all seem to work.  I also tried the K3 with another 
> computer and was unable to communicate with it.  However, I also tried 
> a direct serial-to-serial cable from the K3 to the first computer, 
> which has a serial port, and was also unable to communicate.  I am now 
> unsure of the location of the problem.  I am willing to go with 
> whatever works.
>