[Asterisk-Users] Qs about FXO/FXS cards

[Rich Adamson]

> I am going to be putting together my first * system using FXO/FXS
> interfaces. All the systems I have set up thus far have been pure VoIP
> setups.
> 
> The system I need to set up should have 3 FXO interfaces and 1 FXS
> interface, as well as several SIP phones. I have noticed people
> complaining about Digium's TDM cards - are these isolated incidents or
> are these cards unreliable? I intend to get the TDM400P with the
> necessary FXO/FXS boards - can I expect the installation to be somewhat
> straightforward? Any tips to avoid grief?

I think the best that anyone can estimate at this time is that a problem
exits of some sort and it might be related to a combination of factors,
one of which seems to involve specific motherboard designs. There are
far too many people complaining about the same issues with the TDM card,
several of which opened cases with digium support and got no response.
It should be fairly obvious from the many postings on this list since 
that card was announced that something is not right, and at least some
of those systems have digiums T1 cards on the exact same pci bus that
are operating just fine.

If you read through the archives, you'll see a number of people flapping
their jaws using adjectives and adverbs about what they think the issue
happens to be, but the majority (if not all) don't have a TDM card and 
apparently wouldn't touch one with a ten foot pole.

What is obvious at this point is:
a. no one on the -user list is going to fix (or even hint with any 
   degree of authority) the root-cause
b. don't ever post anything to the -dev list regarding a TDM card as
   that is NOT the forum for digium cards or drivers,
c. digium support is not addressing the issue, and,
d. the amount of effort required to support the TDM card (stop *, restart
   the drivers, start *) in its present condition is far greater then
   what any reasonable non-technical customer will endure.

Since this has been an on-going battle, I'd suggest avoiding the TDM
card totally, or, take the 50-50 risk to see how high you can raise
your frustration level.

> Would it make more sense to get 3 cheap X100P's and use some kind of ATA
> for the FXS? Will obviously save a whole bunch of money, but will there
> be significant added complexity?

Three x100p's are likely to cause even more issues due to the high level
of system interrupts. (Note: digium has removed them from their web site.)

Current experience... three spa-3000's are far more stable then a TDM
card, and you'll get three fxo's plus three fxs's for less money.