Here is how it is to see really used dialect for span: 1. To write down erroneous /etc/openzap/openzap.conf - nonconsistent trunk_type $ cat /etc/openzap/openzap.conf [span zt] name => OpenZAP number => 1 trunk_type => Z1 #trunk_type => E1 b-channel => 1-15 d-channel => 16 b-channel => 17-31 [span zt] name => OpenZAP number => 2 trunk_type => Z1 #trunk_type => E1 b-channel => 32-46 d-channel => 47 b-channel => 48-62 [span zt] name => OpenZAP number => 3 trunk_type => Z1 #trunk_type => E1 b-channel => 63-77 d-channel => 78 b-channel => 79-93 [span zt] name => OpenZAP number => 4 trunk_type => Z1 #trunk_type => E1 b-channel => 94-108 d-channel => 109 b-channel => 110-124 2. And then in error message of mod_openzap's loading it's possible to see dialect's index: 2008-09-19 16:12:48 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 1 mode: 0 dialect: 0 error: Unknown trunk type! 2008-09-19 16:12:48 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 2 mode: 0 dialect: 2 error: Unknown trunk type! 2008-09-19 16:12:48 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 3 mode: 0 dialect: 4 error: Unknown trunk type! 2008-09-19 16:12:48 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 4 mode: 0 dialect: 6 error: Unknown trunk type! - this conforms to PRI configuration: <configuration name="openzap.conf" description="OpenZAP Configuration"> <settings> <param name="debug" value="1"/> </settings> <pri_spans> <span id="1"> <param name="dialect" value="q931" /> ... </span> <span id="2"> <param name="dialect" value="national" /> ... </span> <span id="3"> <param name="dialect" value="dms"/> ... </span> <span id="4"> <param name="dialect" value="5ess" /> ... </span> </pri_spans> </configuration> But if now to write unknown FreeSWITCH dialects into a PRI configuration, <span id="3"> <param name="dialect" value="XYZ" /> ... </span> <span id="4"> <param name="dialect" value="euro" /> ... </span> </pri_spans> </configuration> - then we'll get such mistake message: 2008-09-19 16:25:44 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 1 mode: 0 dialect: 0 error: Unknown trunk type! 2008-09-19 16:25:44 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 2 mode: 0 dialect: 2 error: Unknown trunk type! 2008-09-19 16:25:44 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 3 mode: 0 dialect: 2 error: Unknown trunk type! 2008-09-19 16:25:44 [ERR] mod_openzap.c:1638 load_config() Error starting OpenZAP span 4 mode: 0 dialect: 2 error: Unknown trunk type! It's visible that: 1. FreeSWITCH doesn't identify dialects "euro" и "XYZ"... 2. Insted them it substitutes dialect "national" => 2 without any debug message.