Network Cards may be integrated into the motherboard, but more often than not, they are add-on cards like the one pictured above.  The above pictured network card (also called ethernet cards or NICs) is commonly referred to as a "combo card".  The jack resembling a TV cable connection is for coaxial cable, running on a 10 base-T network and uses a BNC connector.  The RJ-45 jack is for Category 5 and similar cables and runs on a 10 base-T connection, also.  This is an ISA card.