A semi-wireless electric switch system controls power to electrical fixtures by multiplexing to remote solid state relays installed in the wiring junction of the fixtures. A mobile application is provided which may be downloaded and installed on the user's smartphone, tablet, laptop, or other electronic device. The application may be used to control the switch system. Wall switches are replaced by small flat-screen visual displays with touchscreen capability, which enable an installation technician to install additional lights, wall outlets, and other fixtures using existing wiring. Each relay has a preprogrammed three-digit code prefix, and receives and executes a simple digital command to turn on or turn off power to the fixture through the existing wiring.