[Elecraft] USB to Serial adapter ~ question for Don

[Eddy]

That's what I surmised Don, as always many thanks!!

73

ed




On Wednesday, November 6, 2013 5:46 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
 
Eddy,

The answer is an emphatic YES.  That cable is NOT suggested, it is 
mandatory to keep from damaging your K2.
The K2 uses only 3 of the RS-232 level signals, TXD, RXD and Signal 
Ground, and those conform to the normal RS-232 pins for those signals.
The other pins in the K2 AUX IO connector (note that it is NOT labeled 
RS-232), are internal K2 signals used for controlling externally mounted 
Elecraft gear - the KAT100, KRC2, an externally mounted KPA100, the XV 
series transverters.

If those internal signal lines are subjected to RS-232 voltage levels, 
damage to the K2 can occur.

A proper USB to RS-232 converter (or adapter) should implement all the 
other RS-232 signals, and the voltages can be as great as +/- 25 volts.

So yes, you do need the 'special cable' - it has only 3 connections to 
the serial port - TXD, RXD and signal ground.  You do not have to make 
it a long cable, but it must be present.

You might want to build a short 'special cable' and attach it 
permanently to the K2 - then you can plug either the serial adapter or a 
standard serial cable into that short 'special cable'.

In short, never connect an RS-232 cable to any device connector that is 
not clearly labeled as RS-232.  Those 9 pin DE-9 connectors may look the 
same as a computer serial port, but they may just be a convenient 
connector.  I have several on my antenna field connector panel that are 
definitely not RS-232, they are just 9 pin connectors.

73,
Don W3FPR



On 11/6/2013 7:27 PM, Eddy wrote:
> Don, regarding your answer to Tom's question about a USB to Serial adapter, you suggested the Keypan unit which I found on Amazon for $15......my question about serial and the K2, do I still need to make a custom serial cable for my K2 as suggested in the K2 manual?
>