With these expansion modules, you can easily add 48 or 96 buttons to the existing programmable keys on the IP or digital phones. The PKM Interface Module allows the PKM 48 to be easily connected to an IP or digital phone. These additional personal keys can be programmed as feature keys, speed dial keys, direct station select (DSS) keys, or line appearance keys. Each key has a line status indicator that works the same way as those on the associated telephone. The additional keys are easy to program through the telephone or by the system administrator. PKM 48-button units can also be attached to the Mitel 5540 IP Console, when used on the Mitel SX-200 IP Communications Platform (ICP), to extend DSS / BLF capabilities to the console operator.