Wiring optical incremental encoder
Just connect Vcc and GND, you don't have to limit current on Vcc and GND. Ch.A and Ch.B are your outputs. The maximum supply current (26mA) in combination with maximum output current (25mA) implies that you do have to limit the output current. Notice that you have two outputs that can be active at the same time. In my opinion maximum output current per pin should be limited to 25mA / 2 = 12.5mA. I personally would advise to keep the output current a fair bit lower (factor 2..10) than the these maximum ratings.