[WriteLog] W5XDMulti+ Keyer and USB serial

[Jerry Pixton]

Wayne, Dick, et al

Thanks for the information. I have gone back to the native serial comm port 
I have been using for ever with this device. I have never had any problems 
there. I was trying to free up another native serial port to run FSK on 
both radios.

Sometimes we do scratch the capabilities of our equipment. May be one more 
reason to look at two computers for two radios, hi

Jerry, W6IHG


At 06:44 PM 2/3/2003 -0600, W. Wright, W5XD wrote:
> > I see a similar behavior on the Entrega/PortGear device.
> > Wayne posted a
> > note a few months ago mentioning the behavior, so I'm guessing it's
> > somewhere on his list to try and figure out why it happens.
> >
>
>Well, that guess is not quite right. The MK-1100 keyer uses the modem
>control lines,
>DTR/DSR/RTS/CTS for communications between WL and the keyer, while the
>TXD/RXD lines pass through for rig control. The problem with most
>USB-to-serial adapters is that they have very long delays between the
>software interface that WL sees and the hardware DTR/DSR/RTS/CTS signals at
>the ports. (The delay might be on outputs or inputs or both--it doesn't
>matter.). Some are a few milliseconds, but some or hundreds of milliseconds.
>For comparison, the delay in motherboard serial ports is less than about 1/4
>msec--too fast for me to measure in software.
>
>The protocol between WL and the MK-1100 is such that the data eventually
>makes it through in spite of the delays, but too long to be useful.
>
>The way WL handles those long delays can make WL's keyboard response "jerky"
>(long delays in responding to keystrokes). I am considering modifications to
>remove this jerkiness, but I can't do anything to overcome the delays in the
>hardware.
>
>Wayne
>
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Dr. Jerry R. Pixton, PIXOS Designs LLC
http://www.pixos.com/designs/RadioTuner/
jpixton at shentel.net
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