[Asterisk-Users] Using Hylafax and Digium T100P

[Rich Adamson]

> > In the post that I was responding to, the writer hinted his understanding
> > was that T1 to T1 channel connections didn't involve any asterisk code.
> > His impression seemed to suggest that codec selection, etc, wasn't a
> > factor since the analog fax modem signals were coming in one T1 channel
> > (or PRI channel) and going out another without passing across the * pci 
> > bus. (Purhaps I've have read too much into his post though.)
> > 
> > If the analog modem signals are transitioning the * pci bus, there 
> > is a high likelihood the modem signals will not be accurately handled 
> > by * and thus limit the speed at which the fax modem will function.
> > Don't read that as "it will", but rather "it might". (See many past
> > posts relative to analog modem usage through asterisk, and many other
> > posts where readers didn't understand the significance of g711 usage
> > and analog modems via asterisk.)
> 
> I think the data may get to the zaptel driver on a native bridge. I'm not 
> sure if there is a cross-connect in the actual TE405P card. However, 
> barring missed interrupts there should be no frame slips and no signal 
> degradation when passing a call from one T1 to another T1 on the same 
> TE405P card. They all share the same clocking and there should be no 
> slips, missing data etc. 

I don't have a 405P card here to test, but I'm fairly certain the card 
does not have any onboard logic to cross-connect channels, implying all
cross-connects happen on the zaptel/asterisk side of the pci bus. Given
the track history of missed interrupts (etc), its fair to adjust the
expectations from "will work" to "might work".

In a recent discussion with technical folks at Supermicro relative to
pci latency issues, comments like "Latency is the biggest issue since 
Intel is using I/O hubs on most of their products" imply the later chip
sets are worse then older ones (for whatever reasons). Their lowest
latency motherboard recommendation is actually a two year MB.

I would not be a happy camper if I invested in 405P cards, etc, with
the expectation that fax "will" work and then find out later it doesn't,
followed by posts that we've all seen relative to "get a decent MB".