In the elevator industry, "emulator" often refers to the software interface that runs the service tool on a PC, or the simulation mode used for training. The Otis Service Tool is not typically an app you run inside a standard Android emulator (like BlueStacks); it is specialized Windows-based software.
If you’re an elevator technician or student needing offline access to OTIS service procedures, this emulator + a decent PC (like PC Top) does the job. Just don’t expect modern UI or hand-holding. emulator service tool otis on pc top
Here’s a for the OTIS emulator service tool on PC: Emulator Service Tool: Otis — Overview and Guide (PC)