[asterisk-users] [Zaptel] Why no driver for PCI voice modems?

[Tilghman Lesher]

On Tuesday 31 March 2009 08:09:39 Fred wrote:
> Considering how cheap PCI modems are compared to even the cheapest
> PCI hardware from Digium, OpenVox, Sangoma, etc.... I was wondering
> why Zaptel can't be used with those to connect an Asterisk server to
> a POTS line for low-level use? It just seems overkill for SOHO users
> who only get a few calls a day.

If half-duplex audio is good enough for you, sure.  That is, if you can deal
with audio flowing in only only direction, it would work.  This is usually a
hardware limitation that cannot be overcome by changing the driver.  Only
a fraction of the hardware available is actually capable of full duplex audio.

> Is it because those modems are usually Windows-specific, and it would
> be too much work to have a working driver for Linux?

It's not a matter of too much work.  It's a problem of having the right
information from the manufacturer and a problem of finding a person
skilled enough to write the driver.

> What about a Windows port of Asterisk and some glue to connect
> Asterisk to the modem driver?

This has been done before, in theory.  Asterisk certainly compiled on
Windows, although from what I understand, it did not work particularly
well.  You would also need people to maintain the port, as bitrot is what
happened to all of the previous efforts, after the porter went on to other
projects.

What it really comes down to is a value proposition:  if you are not willing
to spend the money to purchase a hardware card for a little over $100 for
a single port card, then are you willing to invest your time into writing
and testing either a driver or a port of Asterisk to Windows?  Remember that
either proposition is likely to need weeks (or months) of your time.  Is your
time better spent on that task, or is your time better spent working on other
jobs that would earn you the money to purchase a card from a company that is
willing to maintain the drivers and the software, to ensure that both continue
to work?

-- 
Tilghman