KXUSB Signal Levels Was: Re: Connecting a KXUSB to the K2 RS232

[ANDY DURBIN]

"can you confirm that the KXUSB uses TTL signal levels rather than standard RS232 levels? "

I just put a  scope on a breakout of the signals between a KXUSB and my KAT500.  I needed to do this for another purpose anyway.   The simple answer seems to be the (my) interface is neither TTL nor RS232 compliant for voltage.  The PC out data swings between  0 V and  5 V.  The response data from KAT500 swings between  0 V and 9.4 V but with horrible negative going spikes at each return to zero.

Now I don't know if I should interrogate my KAT500 with RS232 or TTL.   I certainly can't feed the KAT500 responses to the low level inputs of an Arduino.  However, it would seem to be safe to use the KXUSB to interface with a TLL compatible device.

73,
Andy k3wyc

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[ANDY DURBIN]

"but with horrible negative going spikes at each return to zero"

I need to correct that.  The spikes are somewhat random.  For some interrogation responses the data word is completely free of negative going spikes.  For other responses there are multiple negative going spikes.  When the spikes are present they are undershoots and ringing that happens on the falling edge of the data.   I have not found any pattern to the occurrence and cannot rule out the possibility that it is a measurement artifact.    Anyone else willing to scope the PC data output of a KAT500?

Any comment or explanation from Elecraft?

73,
Andy k3wyc


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