Obtain an IP Address Automatically option (access points) Obtain DNS Server Address Automatically option (access points) omnidirectional antennas costs online directories hotspots locating 2nd online shopping Wi-Fi PC Cards 2nd open hotspots 2nd Open System Interconnection (OSI) 802.11 layers operating systems laptops Wi-Fi PC Card installation 2nd PDAs 2nd Ordinance Survey Web site Ordnance Survey Web site OS. [See operating systems] oscillations radio frequencies OSI (Open System Interconnection) 802.11 layers