Hello, i have printer encoder which i need to attach to Arduino Leonardo R3, but i don't know the values of +, GND, RX, TX. Can you help me? Printer: MFC-465CN (Specifications | MFC-465CN | United States | Brother)
I cannot find reference to a B30 7914 sensor but what makes you think it uses serial?
Looking at the images you poster I would guess that pin 1 (your numbering) is power, pin 2 is ground & pins 3/4 are the equivalent of A & B. I would expect them to be digital outputs that either pull high or low when the gate is interrupted.