Does the Automatic Tool Changer require an air compressor?

Yes, it will require a small air compressor that is capable of outputting 125-130 PSI of air pressure.  We use a small pancake compressor from Harbor Freight that we got for $119.00.  They have pricing that ranges and sometimes you can get it for even less money. The direct link to the product is: https://www.harborfreight.com/air-tools-compressors/air-compressors-tanks/air-compressors/6-gallon-08-hp-150-psi-oil-free-pancake-air-compressor-58636.html

Note: You will need a 1/4 in. FNPT x 1/4 in. I/M Steel Plug fitting to match your compressor’s hose.  Here is one from Home Depot: http://www.homedepot.com/p/Husky-1-4-in-FNPT-x-1-4-in-I-M-Steel-Plug-12234HOM/205330359