HSS86 Closed Loop Stepper Drives
Overview
Closed loop stepper drives with STEP/DIR interface. They are often marketed as being "Leadshine" brand, but I'm not sure if that's really the manufacturer. It might be "JMC".
Online Resources
JMC 2HSS86H-KH-xx Hybrid Stepper Servo Drive Manual
HSS86 2-Phase Hybrid Stepper Servo Driver
DIN Rail Mount for Stepper Drivers 2HSS86H and 3HSS57 or DM556 [3d printable] (shows PCB photos)