The PWS-4504 is an optional SDI interface board that adds SDI I/O interfaces to the PWS-4500 live server. The PWS-4500 is equipped with the two SDI interface boards as standard, which handles up to four HD I/O signals or up to two 4K I/O signals. Up to two PWSK-4504 boards can be installed, which enables to handle up to eight HD I/O signal or up to four 4K I/O signals.