[Elecraft] ACOM 2000A and Elecraft K3

[Bill Turner]

I think I have figured out the connection issues when using a K3 with
an ACOM 2000A.  I wrote up the following mini-tutorial to try to
clarify what is, to me, a confusing situation. 

Please read it and let me know if I have made any errors and whether
you find it helpful.

If you find it helpful, feel free to copy and distribute any way you
wish. 

Thank you,

73, Bill W6WRT

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When operating an ACOM 2000A with an Elecraft K3, there are two
possible modes of frequency control. Each mode requires a different
cable. 

When a PC is NOT connected: 

Use a cable like that shown in figure 7.6 of the ACOM 2000A manual.
You should set the K3 AUTOINF menu option to "1". In this mode the
2000A will poll the K3 for band data and will change bands
accordingly. The K3 will also send band data when you manually change
bands on the K3. 

When a PC IS connected:  

Use the cable shown in figure 7.2 in the 2000A manual. You should set
the K3 AUTOINF menu option to "nor".  Note that this cable does NOT
have the TXD wire going to the ACOM 2000A, but it does have the TXD
wire running between the legs of the Y connector. This cable can be
either a single cable terminating in two DB-9 connectors or it can be
a single cable with a "Y" adaptor connected at the DB-9 end. In either
case, it must be the electrical equivalent of figure 7.2.  In this
mode, the ACOM 2000A gets band data information ONLY from the logging
program, not from the K3. If you close the logging program, the ACOM
2000A will NOT follow band changes from the K3. You can still do band
changes by sending a "dit" as explained in the ACOM 2000A manual.