On Sunday 05 Jul 2015, Luca Bertoncello wrote: > Hi list! > > I noticed that when the phone of my wife calls the gsm codec will be used, > but if someone calls the phone, alaw will be used:
> Could someone explain me why? > Second question: I think, ulaw/alaw are better then gsm, isn't it? > If so, how can I change it? GSM is the native codec used for calls to mobile phones; it uses lossy compression to achieve a low bit rate. A-law is the native codec used by physical exchanges on the land line network (PSTN and ISDN). It is non-lossy. It works by arranging the "steps" closer together near the zero line, and further apart away from it; so the difference between the actual signal and the nearest digital representation is small in proportion to the signal. To force the use of a-law, you need something like disallow=all allow=alaw at the top of the configuration file for the calling technology in question (sip.conf for SIP, chan_dahdi.conf for DAHDI, &c.). If you want to force a specific device to use a specific codec, then put an allow in the section for that device. -- AJS Note: Originating address only accepts e-mail from list! If replying off- list, change address to asterisk1list at earthshod dot co dot uk . -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
