1-Way refers to key fobs used for car alarms, remote starters, or key less entry systems that connect to a vehicle.
1-Way key fobs send a signal ONE-WAY (ONE DIRECTION) from the key fob to the vehicle, but do not receive a confirmation signal back from the vehicle. They do not provide any status or vehicle updates.
1-Way key fobs are regarded as the most basic of control methods for car alarms, remote starters, or key less entry systems.
See below for a common style of 1-way key fob: