Setting and reading linuxCNC variables externally

Hi,  I am new to the forum and linuxCNC.

I am in the process of building a CNC machine that uses LinuxCNC/Mesa 5i25 & 7i76 board/ with DMM servos. 

The machine I am currently working with is a HAAS gantry mill.  We wrote a G code program for the HAAS that communicates with a Linux box over a serial port. The Linux box interfaces with a laser and sonar measuring devices to map surfaces.  The HAAS allows me to read and write variables.  On the HAAS we use these variables to set the X/Y/Z axis and also a few semiphoress to keep the two processes in sync?

Does LinuxCNC have an equivalent way that I can read and set variables using an external program?

Thank you!

len

I need more than a pin for X/Y/Z coords.