I guess I'm missing something with this setup: Freeswitch-1.6.19 built from source on Win 8.1, com0com 3.0 signed, pair on COM6 and COM7 the and soft modem for fax server is on COM7 I had to set number of modems to 6 in config, otherwise I was just getting no modems available. Mod_spandsp sees the port: 2017-11-29 23:43:52.885349 [DEBUG] mod_spandsp_modem.c:371 Modem COM6 [INIT] - Changing state to INIT 2017-11-29 23:43:52.885349 [INFO] mod_spandsp_modem.c:373 Modem [COM6]->[(null)] Ready but when I bridge to modem/6/123 I get: 2017-11-29 23:44:49.203916 [ERR] mod_spandsp_modem.c:1390 Modem COM6 In Use! 2017-11-29 23:44:49.203916 [ERR] mod_spandsp_modem.c:1398 No Modems Available! 971de557-adb4-4a19-9e7d-ab4f13b954be 2017-11-29 23:44:49.203916 [ERR] mod_spandsp_modem.c:862 Cannot find a modem. The same com0com setup works with an old T38Modem with no issues. Any suggestions are really appreciated Dennis