A wireless ISP (WISP) provides fixed wireless internet access between a central node and client devices using line-of-sight radio connections. It uses spread spectrum technology like direct sequence spread spectrum or frequency hopping spread spectrum in unlicensed frequency bands. WISP networks can be configured in point-to-point or point-to-multipoint topologies to connect multiple clients. Proper antenna selection, placement, cabling and configuration are required to set up an operational WISP system.