Why Fight it?

smgvbest, are you talking about a 7i76 board? If I understand the OP correctly, he is not planning to use one. He plans to connect a 5i25/6i25 directly to the Tormach Control Board which will out put Step/Direction and has other I/O for limit switches and VFD Spindle Control (but not encoder input).

gryphon68 wrote: smgvbest, are you talking about a 7i76 board? If I understand the OP correctly, he is not planning to use one. He plans to connect a 5i25/6i25 directly to the Tormach Control Board which will out put Step/Direction and has other I/O for limit switches and VFD Spindle Control (but not encoder input).

Even then, the 5i25 has a second header which could easily have an encoder counter on it.

Yes, my bad. my head is on the lathe more than the mill and I was thinking lathe.
But as mentioned by andy, one could use the other port on the mesa and a BOB to add the encoder.