Pulse counter advise

[endor]

Hi,
I have successfully installed ESP Easy on an ebay nodemcu dev board and plan to use this for energy monitor.

I have a pulse sensor that i obtained from a proprietary energy monitor that i will use, three wires no visual electronics and a RJ-11 connector.

I guess i will just connect 3.3v, GND and connect the data output to a GPIO pin?
But.. do i need any pull up or pull down resistors as best practice for this type of installation?

Any other recommendations for this type of installation? Should i consider sleep modes, certain read intervals etc?

[endor]

Well. i have experimented a bit now.

I have tried various gpio ports without success, they do not seem to react to +3.3v input signals, only gnd signals.

The only one that is actually registering any values from +3.3v is GPIO 15, is it safe to set a 10k pull down on that one and connecting the signal cable?

(nodemcu dev board with ESP-12(E?))