Why not use a voice modem as FXO card?
Bookmark this page:
 Yahoo!
 Google
 Windows Live
 del.icio.us
 digg
 Netscape
|
|
||||||||||||||||||||||
|
Posted by John Doe on April 30, 2006, 9:50 pm
Please log in for more thread options Hi I browsed through the archives, but didn't find a very good explanation as to why we can't use a good voice modem as FXO card for small setups (read: cheap). Is it because their CODECs suck, or they don't support enough of them? Thanks. | ||||||||||||||||||||||
|
Posted by Enzo Michelangeli on May 1, 2006, 3:27 am
Please log in for more thread options ----- Original Message ----- As far as I know, most (all?) voice modems are half-duplex: they can send or receive voice, but can't do both things at the same time. Moreover, their codecs are usually based on some variant of ADPCM, and the driver should transcode the data into some other format suitable for VoIP. All in all, it's just not worth the trouble. On the other hand, some Winmodems (or Linmodems, if we prefer a Penguinically-correct designation ;-) ), i.e. data modems where the data modulation/demodulation is offloaded to the CPU, can be adapted as FXO cards just rewriting their software drivers. This is not trivial (requiring the knowledge of the specific hardware) but was done by Digium for two models, one based on a Motorola chipset and another on an Intel chipset. They used to be sold under the names "x100p" and "x101p" respectively. Digium has now discontinued them, but there are still several third-party vendors of compatible hardware: just check the hits at http://www.google.com.hk/search?q=x100p . See also: http://www.voip-info.org/tiki-index.php?page=X100P+clone Enzo | ||||||||||||||||||||||
|
Posted by John Doe on May 1, 2006, 3:40 am
Please log in for more thread options
On Mon, 1 May 2006 15:27:30 +0800, "Enzo Michelangeli" (snip) Thanks for the links. I'm about to order a couple of those X10?p cards for my first test Asterisk setup, and see how they fare. | ||||||||||||||||||||||
|
Posted by Raqueeb Hassan on May 1, 2006, 1:28 pm
Please log in for more thread options
> See also: http://www.voip-info.org/tiki-index.php?page=X100P+clone
IMHO, most clones can't display the incoming call's callerID. -- Raqueeb Hassan Bangladesh | ||||||||||||||||||||||
|
Posted by John Doe on May 1, 2006, 2:29 pm
Please log in for more thread options
wrote: >IMHO, most clones can't display the incoming call's callerID.
Uh-oh... That's an important feature :-/ Does someone know about real clones as advertised on eBay (http://search.ebay.com/fxo-asterisk), such as... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9719116318 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9718408471 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9720092845 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9718298351 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=9718788040 Thank you. | ||||||||||||||||||||||
>
> I browsed through the archives, but didn't find a very good
> explanation as to why we can't use a good voice modem as FXO card
> for small setups (read: cheap).
>
> Is it because their CODECs suck, or they don't support enough of them?