How to change the rail horizontal offset. Warning: the next section will give you a headache. ** To change the plan offset of a rail is confusing: There is an instance property for each railing, but using instance properties for such global changes is a nightmare for inconsistency.
Simplex is a communications mode in which only one signal is transmitted, and it always goes in the same direction. The transmitter and the receiver operate on the same frequency.
Simplex communication is a communication channel that sends information in one direction only. A duplex communication channel requires two simplex channels operating in opposite directions. The ITU definition of simplex is a communications channel that operates in one direction at a time, but that may be reversible; this is termed  half duplex  in other contexts. For example, in TV and radio broadcasting, information flows only from the transmitter site to multiple receivers.