UNI directional circuits are related to Ports with the TxRx property set to either Tx or Rx, and when the circuit is related to a port, a direction must be set to either AB or BA - as seen in the screenshot below.
The following diagram is an example of a UNI Directional circuit with 2 related Ports set in an AB direction
A UNI Directional circuit can also have Ports that are set in an AB and BA direction, as shown in the diagram below.
Add Circuit to Port
For Uni directional circuits
When an equipment's port is right clicked, and the required Circuit instance is placed in Focus, that circuit can be added to that port as shown in the screen shot below. Furthermore the port's transmission direction can be set on-the-fly, by selecting either the A-B or B-A option.
From the Equipment form tab:
