[Asterisk-Users] Ordering digital trunks?

[John Laur]

> > I feel like a T1 with 24 channels should suffice, but what exactly
do
> > I order and what to I have to have in my asterisk unit to interface?
> > Does the line they terminate just plug into a T100P or do I need
some
> > extra hardware? What services do I need to be sure I order on the
T1?
> > Is there a way using the T100P to dynamically allocate unused voice
> > channels for data?
> 
> There is config options for this, but you will want to have a PRI to
do
> this. A PRI only gives you 23 channels to work with. This will also
help
> make sure your FAX lines are clean as can be. You will want at least a
> block of DID numbers.

OK, that basically covers the main question. Thanks very much for the
response.

> With your question about dynamic allocation of empty channels for
data,
> you would have to find someone who will let you dial in and bond up
> channels. Then you need to calculate the estimated number of lines
used
> a any time, add in a bit for the idle lines so new calls come in, and
> your left with the number of possible 64k channels for data. To take
> your low estimates, 6+4+1 = 11 + 3 for spares and you have 14. 23-14 =
> 9*64kbit. So your low usage, high speed bandwidth is ~576kbit. If you
> don't like this speed, you really need to think about maybe a DSL line
> to augment or be your bandwidth.

This kind of speed is fine for my purpose. This connection would be only
for emergency use when our primary (6 megabit wireless) link fails, and
our ISP would allow us to use it for backup purposes only at no
additional cost.

> > Finally, how do I get the best fax performance for two analog fax
> > machines out of this setup? Will an ATA-186 serve, or will I get
much
> > better performance using a TDM400P with zaptel bridging?
> 
> The TDM400P would be a good choice, and price isn't too much
different.
> Not to mention that it will help making sure your T1 is up as it is
> easier to configure.

Well, I was asking because I already have some ATA-186's that I am only
dinking around with that could actually be used. I guess I should test
them to see how (non-T.38) faxing works via asterisk and if the
performance is not good, I'll move to the TDM400P.

Thanks again,
John