John-100, this is very helpful. When asked about a "controller" earlier this was what I was talking about. The installation manual was rather lean in the details. Here is the link to how to control the laser using PMW.

CNC Laser Build Log

The PWM connects to Output #1 to the VFD to control spindle speed in some automagic way. The MX4660 outputs on Output #1 & #2 a 12vdc with a + and - lead and PWM can be assigned to either Output. I understand the laser TTL is a high of 5 VDC and a low at 0 VDC. Other research on the same site suggests using one of their "controller' to manage the laser. Hence my confusing surrounding a "controller".

I looked up the arduino ULN2003 board on eBay. These are cheap. The one I am looking at that most closely matches your diagram is

https://www.ebay.com/itm/DC-5V-Stepp...sAAOSwA3dYNkB-

Is this what you had in mind? How would the laser intensity be controlled? Since the laser has a single TTL+ wire, would the TTL- just be attached to the case?

Thank you very much for taking the time to research and help me. It is very appreciated.

Dave