Airbus58,
The inputs can be summed into the rudder.
The manual rudder control, ie rudder inputs are machanically activated by the cables, the automatic controls, ie turn co-ordination and yaw damper are electrical through the ELACs/FACs.
If you were to have an engine failure and step on the beta bar you are using manual control over the rudder, count the seconds as you wind in the rudder trim, and engage the autopilot. Then the yaw control is electrical with the autopilot trimming the rudder.
Zeke