Did you order the C11G specifically with 2 mechanical relays? I'm finding the CNC4PC website a tad confusing, since there are 2 revisions of the manual, one sports 2 mechanical relays, the other one mechanical and one solid-state, but nowhere I've been able to find if it's available as an option or if it's an "evolutionary" thing (Darwin's into electronics nowadays?

).
I think I'll place an order in the next weeks/month, so I wonder. Next will be the PSUs and steppers, then the mill and the retrofit kit (CNCFusion's)
Regarding Linux, it's not what's bothering me much. I'm a computer systems analyst, and I've worked on many UNIX/Linux platforms. They're not as tough to install/manage as they were in the past (I had to install my first "slackware" distro on a '486 PC - circa 1995 - , over a SCSI cd-rom through a SoundBlaster-16 sound/SCSI hybrid card; it was a bios-less card, so I had to pass a truckload of parameters at the boot prompt simply to boot from the CD, not to mention disk paritioning nightmares which were quite "hands-on") It's the EMC2-related part that intimidates me; as I understand, it's more versatile than Mach (can control multi-axis robots and unconventional machines as well as mills and lathes), but as always it comes with the other side of the medal; complexity.
OTOH: LinuxCNC is available as a boot-from-CD distro too, might be an easy way to try it. It uses Ubuntu, which is AFAIK one of the friendlier (maybe not friendliest) distros around. Since it's built over the LTS (long-term support) version of the distro, this means security patches should be available for a long time. Using a prebuilt distro is far easier than having to build emc2 from source (belive me, building from source can be a very nasty thing when you hit package dependency and versioning issues)
I guess I'll have next winter to thinker with EMC2, perhaps as a dual-boot to Windows/Mach3 on the machine I plan to use.
What do you mean by
I'd like to trigger the tach reverse relay off of the KBCC somehow without hacking into it.
?
The way I used to control the relay looks like - to my own surprise - the "Run-Brake and Forward-Reverse Switches" in KB's "KBPB & KBCC-R SUPPLEMENTAL INFORMATION" doc, if that's what you mean (page 1, 1st column, 2nd row). I don't know how well it could integrate to Mach3/EMC2 though; needs an "on/off" and a "direction" signal. I used 5V relays (they switch on with a 5V "TTL" signal that the C11 will output, but they can handle up to 250VAC/220VDC@3Amps on the other side; since the KBCC should put out 28VDC@ a few milliamps, the relays should be more than tough enough, I guess). Bought them at Digikey, along with DIP sockets (16 pin) and block terminals, so I solder the sockets to the proto-board and plug-in the relays, if I blow a relay the repairs will be easier. All components are 0,1" pin spacing so they're standard and pre-drilled proto-boards are easy to find.
Thanks again for your comments!