CSU/DSU ( channel service unit / data service unit )
It is a digital-interface device used to connect DTE
You should select the configure DHCP options for proxy DHCP option if the local DHCP server is a Microsoft DHCP server, if you select this option the DHCP server is automatically configured to forward the PXE requests to the WDS server. If the local DHCP server is not a Microsoft DHCP server, you have to configure the DHCP server manually to forward the request to the WDS server.
Basic input/output system
personal trait because it something that just comes to mind