Abstract: Examples described herein are used in timing synchronization systems. A timing synchronization system provides circuits that support bi-directional half-duplex voltage signals (transmit or receive) but protect against incorrect input/output configuration whereby a transmit signal media is connected to a receive port or a receive signal media is connected to a transmit port. The system provides configurable signal propagation by use of parallel connection of two or more buffer in series with a resistor. Various isolation circuitry and resistors can be used to protect against signal transmission during receive mode.