DMX Switchers

I have two Silver color DMX switchers A/B ,and multi switch. I dont know who it was made by , no writing on it , it look just like PD2000/8000. Imput/output uses 3pins.
To me it looks like PD2/8000 ancestors , with knobs, and 3pins out/inputs.

I have two Silver color DMX switchers A/B ,and multi switch. I dont know who it was made by , no writing on it , it look just like PD2000/8000. Imput/output uses 3pins.
To me it looks like PD2/8000 ancestors , with knobs, and 3pins out/inputs.