Hey Tom, hey Bill @Machinist,
nice digital interface. Unfortunately you seem to pay more for it in the US than here in the origin country (MM-1000 DI).
Unlike one might think, it has no ER collet, it’s this proprietary collet. The Mafell FM 1000 PV ER has a true ER 16 collet, but its speed control interface is analog voltage (see manual for the interface specs). But with a pwm to voltage converter (easily available) you can control it with the Onefinity Controller since it allows control of PWM spindle.