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.
----- 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
See also:
On Mon, 1 May 2006 15:27:30 +0800, "Enzo Michelangeli" wrote: (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.
IMHO, most clones can't display the incoming call's callerID.
-- Raqueeb Hassan Bangladesh
Uh-oh... That's an important feature :-/
Does someone know about real clones as advertised on eBay
I dont think its impossible. I read somewhere that Intel 537 chipset modems can function as an FXO. But I havent tried that out myself. But at the moment I have sucessfully used a hardware modem (not a softmodem) as a full duplex VOIP-PSTN gateway, that can route calls. (Usually the modem's audio driver is half duplex.)
Rochana
Cool. Reference? Support for caller ID? :-)
DLink DFM562I is the modem. There is a good AT command reference in their website
Thx.
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