Devices with Direct Station Selection (DSS) are automatically assigned a memory when configured with the AMO SBCSU. The proportion of name keys to DSS keys may be freely selected per telephone. The difference between DSS and name keys is that on DSS keys, the busy condition of the destination is displayed via a LED. If the destination is called despite being busy, call waiting is automatically activated and the destination is called when no longer busy.

By pressing the flashing DSS key (while the destination is being called), it is possible to take the call.

The DSS key must be assigned to one of the freely programmable keys to be able to make a destination entry. This may be achieved with the AMO TAPRO, either by assigning a standard key layout or by assigning the key function individually.