Salve ho installato il 3cx sul mio server windows 2012. Ho configurato du telefoni interni grandstream gxp1200 e un gateway grandstream ht 503. In ingresso tutto funziona regolarmente mentre in uscita , opo aver digitato il numero ed inviato la chiamata si sente un piccolo fruscio della durata di meno di 1 secondo e subito dopo il tono di chiamat libero . Insomma ht 503 non compone alcun numero. Per maggiore chiarezza posto il log del server. Grazie a chiunque sia in grado di aiutarmi! 
[CM503007]: Call(C:6): Line:10001>>091******* has joined, contact
27-giu-2013 17:21:49.719 [CM503007]: Call(C:6): Extn:10 has joined, contact
27-giu-2013 17:21:49.714 L:6.2[Line:10001>>091*******] has joined to L:6.1[Extn:10]
27-giu-2013 17:21:49.693 [CM505002]: Gateway:[HT 503] Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [Grandstream HT-503 V1.1B 1.0.10.3 chip V2.2] PBX contact: [sip:[email protected]:5060]
27-giu-2013 17:21:47.920 [CM503025]: Call(C:6): Calling T:Line:10001>>091******@[Dev:sip:[email protected]:5062] for L:6.1[Extn:10]
[CM503007]: Call(C:6): Line:10001>>091******* has joined, contact
27-giu-2013 17:21:49.719 [CM503007]: Call(C:6): Extn:10 has joined, contact
27-giu-2013 17:21:49.714 L:6.2[Line:10001>>091*******] has joined to L:6.1[Extn:10]
27-giu-2013 17:21:49.693 [CM505002]: Gateway:[HT 503] Device info: Device Not Identified: User Agent not matched; Capabilities:[reinvite, replaces, able-no-sdp, recvonly] UserAgent: [Grandstream HT-503 V1.1B 1.0.10.3 chip V2.2] PBX contact: [sip:[email protected]:5060]
27-giu-2013 17:21:47.920 [CM503025]: Call(C:6): Calling T:Line:10001>>091******@[Dev:sip:[email protected]:5062] for L:6.1[Extn:10]