Dear All, I follow instruction in wiki http://wiki.freeswitch.org/wiki/Mod_gsmopen I am using VS2010. however when i compiled mod_gsmopen still fail.... below is log: 1>------ Skipped Build: Project: gsmlib, Configuration: Release Win32 ------ 1>Project not selected to build for this solution configuration 2>------ Build started: Project: mod_gsmopen, Configuration: Release Win32 ------ 2> Creating library D:\FS_GIT\Win32\Release\mod\mod_gsmopen.lib and object D:\FS_GIT\Win32\Release\mod\mod_gsmopen.exp 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_queue_indication@8 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_channel_perform_mark_ring_ready_value@20 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_mutex_lock@4 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_get_channel@4 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_sleep@8 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol "public: int __thiscall ctb::SerialPort_x::Open(char const *,int,char const *,enum ctb::SerialPort_x::FlowControl)" (?Open@SerialPort_x@ctb@ @QAEHPBDH0W4FlowControl@12@@Z) 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol "public: __thiscall ctb::SerialPort::SerialPort(void)" (??0SerialPort@ctb@@QAE@XZ) 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_rwunlock@4 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_log_printf 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_perform_locate@16 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_channel_perform_hangup@20 2>gsmopen_protocol.obj : error LNK2001: unresolved external symbol __imp__switch_mutex_unlock@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_request_uuid@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_xml_attr_soft@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_codec_destroy@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_fire_detailed@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_xml_attr@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_set_caller_profile@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_time_now@0 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__dtmf_rx_parms@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__dtmf_rx@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_codec_init_with_bitrate@40 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_caller_profile_new@48 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_queue_dtmf@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_test_ready@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_separate_string@16 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_file_write@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_is_number@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_timer_next@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_event_set_data@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_timer_sync@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_add_header_string@16 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_thread_create@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_set_write_codec@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_thread_launch@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_get_name@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_threadattr_stacksize_set@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_set_private@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_get_private@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_get_pool@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_add_body 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_xml_free@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__dtmf_rx_init@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_get_uuid@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_swap_linear@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_test_flag@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_threadattr_create@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_loadable_module_create_module_interface@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_snprintf 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_xml_child@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_reserve_subclass_detailed@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_loadable_module_create_interface@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_caller_profile_clone@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_thread_join@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_set_name@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_get_header_idx@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_direction@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_add_stream@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_xml_open_cfg@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_set_read_codec@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_default_dtmf_duration@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_chat_send@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_perform_mark_answered@16 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_perform_mark_pre_answered@16 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_timer_init@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_destroy@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__dtmf_rx_get@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_copy_string@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_free_subclass_detailed@8 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_get_body@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_timer_destroy@4 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_add_header 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_event_create_subclass_detailed@24 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_mutex_init@12 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_channel_perform_set_state@20 2>mod_gsmopen.obj : error LNK2001: unresolved external symbol __imp__switch_core_session_perform_destroy@16 2>D:\FS_GIT\Win32\Release\mod\mod_gsmopen.dll : fatal error LNK1120: 76 unresolved externals ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 1 skipped ========== Regards,