Marco Signorini wrote: > Joseph wrote: > >> On 03/04/09 15:44, Marco Signorini wrote: >> >> >>> Hi Joseph. >>> I've spent some time tuning the SPA3102 FXS line input and output gain >>> and I think that this is an important variable. >>> Let's try to record incoming and outgoing fax tones with asterisk on SIP >>> channel (disabling the fax detection on SPA and sending fax inband) and >>> look at the recorded file with a wave editor (Audacity). >>> I had better results if the maximum level is near half to the full >>> dynamic. Then switch to T38, if you need it. >>> >>> >> As I remember I have experimented with gain on PSTN line as well but have >> reset back to default. >> I have: >> SPA To PSTN Gain:0 >> PSTN To SPA Gain:0 >> >> I think "0" is the default. >> >> >> > Yes, "0" is the default. > Is the fax machine connected to the FXS port or do you use the SPA3102 > only as a SIP 2 PSTN gateway? > If you use the FXS port, please take a look at the gain parameters you > can find in the "Miscellaneous" section in the "Regional" page (log in > as Administrator then switch to the "advanced" report). > > Now I've -5 as input gain and -2 as output. I don't know if this could > helps you. > > I regularly do T.38 testing against and SPA3102, and they are quite troublesome. Different FAX machines and FAX modems give very different results. If you put a much longer lead between the FAX machine and the SPA3102 you may find it works a lot better. :-\
If you turn up the gains too much you get clipping, but as long as you don't go too far it shouldn't very sensitive. Regards, Steve _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
