3.7 ANTENNA................................................................................................................. 173.7.1 GSM .................................................................................................................. 173.7.2 WLAN ................................................................................................................ 183.8 ENVIRONMENTAL SPECIFICATIONS..................................................................... 183.9 TYPE APPROVAL AND EMC TESTING................................................................... 193.9.1 GSM .................................................................................................................. 193.9.2 WLAN ................................................................................................................ 193.9.3 ELECTROMAGNETIC COMPATIBILITY (INSIDE EUROPE) ............................ 193.9.4 ELECTRICAL SAFETY (INSIDE EUROPE) ....................................................... 194. GENERAL SOFTWARE SPECIFICATIONS ................................................................ 204.1 SUPPORTED OPERATING SYSTEMS .................................................................... 204.2 INSTALLATION SOFTWARE ................................................................................... 204.2.1 NORMAL INSTALLATION ................................................................................. 204.2.2 INSTALLATION DISK ........................................................................................ 224.3 PROFILES ................................................................................................................ 224.4 ADVANCED SETTINGS ........................................................................................... 234.5 SECURITY................................................................................................................ 294.5.1 WEP KEYS ........................................................................................................ 294.5.2 VPN ................................................................................................................... 304.5.3 PERSONAL FIREWALL..................................................................................... 314.6 WLAN COMPATIBILITY............................................................................................ 324.6.1 LIST OF TESTED ACCESS POINTS................................................................. 324.6.2 KNOWN LIMITATIONS ñ RECOMMENDED SETTINGS................................... 324.7 SOFTWARE INTERFACE......................................................................................... 324.8 SIM SERVICES ( NOKIA OPERATOR WIRELESS LAN) ......................................... 355. AT COMMANDS .......................................................................................................... 365.1 INTRODUCTION ...................................................................................................... 365.2 AT COMMAND SYNTAX .......................................................................................... 365.2.1 S-REGISTER COMMANDS ............................................................................... 365.2.2 BASIC COMMANDS .......................................................................................... 375.2.3 EXTENDED COMMANDS ................................................................................. 375.3 COMMAND LINE ...................................................................................................... 385.4 INFORMATION RESPONSES AND RESULT CODES ............................................. 386. LIST OF AT COMMANDS SUPPORTED BY NOKIA D211.......................................... 39