Hi, I found the same topic created 2 years back in Oct 2007 but it doesn't seem to have the answer yet. I am quite new to FS and having a hard time reading the documentation. Someone could tell me: how would I use a modem and develop an Endpoint in FS that I could bridge the call from VoIP to PSTN. I am a hardware engineer, I am developing this modem and would want to use it with FS. I know that I could simply buy a VoIP Gateway or a zaptel compatible card and use OpenZap. Could someone point me out the direction for the following matters: 1. I feel that I need to develop an Endpoint module, like mod_sofia, mod_iax... that controls my modem so I could bridge the call from VoIP to PSTN ? If that is correct, could someone point me the documentation to start reading about Endpoint interface .? 2. Is there any similar module developed before about controlling a modem using AT Command Pardon my bad English, I don't come from an English speaking country. Btw, this is the first time I participate in a mailing list so I still have no idea how to create a thread or reply to a posting like I normally do in forums. Thanks very much and any helps are highly appreciated. Regards Alex To