Some of our customers have reported problems sending and receiving faxes over VoIP through an analog telephone adapter with some models of fax machines. Some of our customers are using fax machines connected to the UC500 FXS port and some of our other customers are using SPA112 ATAs. For fax calls that use the G.711 codec, we need to be able to suppress the SG3 ANSam tone and force the fax machine to negotiate at a slower speed. We also need to be able to pass through the fax signal subsequent to negotiation while ensuring that the fax call does not get dropped. Is there a way to accomplish this goal in FreeSWITCH?