The OP was asking about an issue with theft of a PC controlling the machine. The suggestion of a DSP was based on that and the RichAuto control system is very compact. The BoB lives in the power/drive control box but the DSP handset is about the size of an over-sized TV remote control and is easy to disconnect and take home :-)
The operation and use of the RichAuto DSP is described very badly. It is not a USB driven controller. It has a USB connection to a PC to allow you to transfer G-Code files between a PC and the DSP but it does not function as a CNC control when you boot it to transfer files. After transferring files, you have to restart it as a CNC controller (and then the PC cannot see it).
Essentially, you use the DSP as a standalone controller and transfer job code between the PC and the DSP with a USB stick you have to keep removing/replacing between PC and DSP. Can be somewhat annoying if you make multiple small changes to your code. Some tricks can be to write the code to use faster movements/RPM but use the DSP to slow the speeds down in real-time to allow for different materials/cutters etc.
As far as an Ethernet control goes, have a look at the AXBB at
https://www.cncdrive.com/AXBB.html
I'll be upgrading from a RichAuto DSP to an AXBB with an extra BoB for additional I/O channels and Ethernet when I can afford it. I kinda like the DSP but a serious limitation is it does not support parametric programming which is somewhat annoying for multiple parts or incremental cutting. You have to do this for yourself in the code generation.
There are other Ethernet options out there so perhaps if we knew more of the requirements others can chime in as well.