For a DIY project I would like to adapt a remote (RF) control
to accept digital signals from MCU. I am not quite sure how the buttons in question work: Are they normal buttons which make near 0 ohm connection or something advanced (it's part of the question).
If I will be able to tap into the button terminals, which circuit would be suitable to "emulate" pressing the button? Can open collector / open drain on from the MCU side work (using common ground with remote control circuit) or additional components are needed? Maybe there are ICs to provide open collectors for 8 connections in at once (would be interesting to know how those might be called)?
For example, http://www.penguintutor.com/electronics/simple-homeautomation-raspberrypi uses relays, which I do not like.
(I can see similar questions like How to "push buttons" on voltage ladder? , but the answer does not contain more detail on transistor approach)