The XFOC-LC belongs to the third-generation of NEXUS optical interface boards. It provides four ports, each with a transmission capacity of 256 channels. Data transmission is plesiochronous at a rate of 1.25Gbps. When it comes to configuring flexible structures or entire networks, the four XFOC ports are advantageous since they reduce significantly the number of interface boards required. The boards can be populated with optical modules on site to allow the number of ports and the connection type (fibre type, distances, etc.) to be adapted to suit the application at hand. Depending on the specific requirement, XFOC-LC boards support various SFP modules including single-mode, multimode, CWDM, long-haul, and duplex modules. A key difference to early XFOC boards is the change of optical connectors, with LC connectors replacing the SC connectors used previously which are twice the size. To meet individual requirements, NEXUS base devices can be equipped with multiple XFOC boards, for example, to connect to other Base Devices or to implement redundant lines. Audio channels are transmitted over optical lines with full 30-bit resolution (24-bit audio plus ancillary data) in an uncompressed format. This provides, for example, for complete and transparent exchange of AES/EBU signals between two base devices.