To Be Determined (TBD) units, also known as generic empties, represent units that a terminal will handle in the future but that are yet to be identified with specific containers. You can create TBD units against equipment delivery orders (EDO) if your site meets both of the following conditions:
Your site uses the Equipment Control option with ECN4 instead of a radio server.
Your site has Front End Loaders and heap-only decking.
TBD units have many of the key properties of a real unit, such as the equipment type, outbound carrier, and freight kind. In addition, you can define the range of acceptable real units that can fulfill a TBD unit, for example by providing a range of serial numbers. Like real containers, TBD units show sequence numbers on sequence sheets and in stow plans, and they acquire work instructions and are dispatched through the Equipment Control module. However, a TBD unit does not have a current position or a specific container number. In place of an actual container number, N4 creates a unique ID and prefixes it with TBD, such as TBD_8038460.
You create and edit TBD units in the N4 client:
N4 client 
Operations Gate Equipment Deliver Orders Equipment Deliver Orders view Equipment Deliver Order form Order Items tab Order Item form Associated TBD Units tab Actions Generate Tbd Units TBD Units form
N4 client Operations Unit TBD Units TBD Units view TBD Unit form
TBD units become part of the open vessel's load list, and you can use the XPS client to view and plan them to the vessel like any other container.
When the CHE operator merges TBD units with real containers, the TBD units are deleted from the N4 system.
To view TBD units in the XPS client:
From the Container menu, select TBD Units.
The TBD Units window opens, listing all existing TBD units.