Each 16DSTU PCB connects 16 digital extensions (i.e. keysets). You can also connect 2-OPX Modules. The 16DSTU has a Mode Switch (for taking the PCB out of service). It also has a status LED that indicates proper PCB operation — as well as a port activity LED that flashes faster as traffic increases on the PCB. You can install up to 2 16DSTU PCBs in a 4-Slot Cabinet, or install up to 6 16DSTU PCBs in an 8-Slot Cabinet. Make a note of the following:
When connecting 2-OPX Modules, continue to observe the System Load Factor.
You must also install a separate power supply for every 2 16DSTU PCBs installed.
In all systems, you must install a 16DSTU PCB in the first universal slot.
In Fixed Slot systems, you can only install the 16DSTU PCBs in the first 2 universal slots.
In Universal Slot systems, you can install 16DSTU PCBs in any universal slot.
You can install either "A" or "non-A" series 16DSTU PCBs in 4-Slot Cabinets
You must install "A" series 16DSTU PCBs in 8-Slot Cabinets.