[Elecraft] Using N1MM to Key a K3 with no outboard keyer

[Dauer, Edward]

The following may test our commitment to the idea that there is no such thing as a stupid question . . . . 

I finally got around to setting up my N1MM logger to key my transmitters without having to use a K1EL or any other keyer -- just the KUSB cable directly from the PC  into the rig.

After hours of frustrating failure, by lucky accident I came across a post on the Internet that gave examples for programming the Fn keys, using N1MM to key a KX3.  Each command line contains the string CATA1ASC before the command KY.  Without the CATA1ASC, hitting the Fn key does nothing.  With it, and with the standard KY programming command, it works -- on the KX3 at least.  My K3 is at my other QTH so I haven't tried this on that rig yet, but here's my question -- what is the CATA1ASC for?  I did a word search in both the KX3 and the N1MM manuals, and in the KX3 Programmer's Guide, and I could find no mention of the CATA1ASC string.  Had I not found the examples on the Internet accidentally I would still be trying to make this work with no success. 

So can someone help me understand what it's about and why I didn't see it in any of the manuals?  Is it something in Windows 10?

Thanks,

Ted, KN1CBR