[Asterisk-Users] Re: Reccomendations for connecting to 3-4 PSTN lines?

[Ivan Fetch]

hi Rich,

   Thank you - that's definitely good information.  Unfortunate about the
Mediatrix non-free firmware, SNMP configs with tied config tool, and
(in)security.  Certainly not a show stopper, but as this is my first real
Asterisk deployment, I think I'll avoid the Mediatrix for now.

   The SPA-3000 does look appealing for the E911 / loss-of-power factors.
I've been playing with a 3000, and despite the lack of outgoing PSTN call
progress, it is a very nice device.

   SO perhaps three SPA-3000's (three PSTN and three phones) and two more
FXS ports (perhaps via a Sipura 2200) to give us our fourth and fifth
phone, is what we'll go with.


Thanks - ivan.



On Thu, 2 Jun 2005, Rich Adamson wrote:

> >    I'm looking to connect Asterisk with three (four in the future) PSTN
> > lines, and would like to get some opinions on the TDM400 Digium card, vs.
> > sip gateways like the Mediatrix 1204, vs. other hardware solutions I'm not
> > yet aware of.
> >
> >    I need the ability to prioritize which PSTN lines are used for outgoing
> > calls (I understand this can be done with the Mediatrix --
> > http://lists.digium.com/pipermail/asterisk-users/2004-February/035926.html),
> > and only answer two of the three lines (the third line will be answered by
> > a directly connected FAX machine, but we can use that line for outgoing
> > calls if the first two PSTNs are in use).
> >
> >    Does the higher cost of something like the Mediatrix ($634) bring
> > advantages to the table over the TDM04b ($337)?  Does the TDM card provide
> > functionality which the sip gateways do not (e.g. incoming / outgoing call
> > progress)?
> >
> > I appreciate hearing from folks who have experience with both methods of
> > connectivity,
>
> I wrote the posting referred to above and its been a while since I've
> touched the 1204, but here are a couple of comments based on the
> firmware that was available at that time.
>
> Mediatrix 1204:
>  - box was designed to work with the 1104 as a toll-bypass solution,
>    therefore it does not implement many sip protocol functions
>  - it functioned very well, good echo cancellation, audio quality, etc.
>  - can only be configured via snmp (no telnet, no web). Their configuration
>    tool _must_ match the version of firmware, therefore for each firmware
>    upgrade you have to remove and reinstall a new config tool (Win32 based)
>  - their snmp implementation had no security, therefore one should not
>    expose the box to the internet (eg, hacking)
>  - each firmware upgrade is a chargable item (not free) and support is
>    basically limited to whatever the reseller can provide (usually not
>    much help). Very limited help on this list as there aren't very many
>    of these implemented with asterisk.
>  - it does not implement the sip "register" function, therefore no way
>    to know when the box might be unreachable (for whatever reason)
>  - documentation sucks unless you are very familiar with reading snmp
>    mib variables, translating their language into telephony and * words,
>    etc. Very steap learning curve, but once working, pretty solid box.
>  - a little company research (in 2004) suggested the company was having
>    financial problems, therefore the only valid assumption one can make
>    is they may not be around in the long run.
>  - I never did test modem use through the 1204, so no idea if faxing or
>    point-of-sale devices will work (or how well).
>
> Digium TDM card:
>  - works fairly well for pure voice use, but quality of echo cancellation
>    and audio is below that of the Mediatrix (and most other comparable
>    fxo devices)
>  - don't even think about using spandsp or any other modem-based audio
>    through the TDM
>  - the latest TDM card revision is rev H. Ensure that is the _only_
>    revision shipped to you (many resellers have earlier revisions in
>    their stock and most of those are prone to failing every week or
>    two requiring a reboot or driver reload)
>  - software support for the TDM is almost non-existant from digium and
>    from the various * lists (there are only a very small number of
>    technical people that understand the drivers, etc, and most won't
>    touch them.)
>
> Sipura spa3000:
>  - slightly more costly then the TDM card
>  - audio quality and echo cancellation about the same as the TDM card
>    but below that of the 1204
>  - somewhat difficult to configure as there are tons of options that
>    are not very well documented, and some options are not fully
>    implemented
>  - highly flexible in exactly how you want the fxo and fxs ports to
>    be configured and inter-operate with asterisk (most generally
>    limited by your understanding, skills, and the amount of time
>    available to experiment)
>  - historically, more stable then the TDM card
>  - if you think through the US E911 and legal issues associated with
>    liability for comm failures, the spa3000 will likely win over
>    any fxo device on the market today for soho environments.
>  - much easier to diagnose pstn line problems if you have the skills
>    and background to understand what its telling you
>  - support sucks and is limited to the reseller (or voxilla.com forum
>    users)
>  - if you've been around Cisco's internal agendas, there is a high
>    probability the sipura devices will improve over time.
>  - early boxes seemed to have power issues (high heat generation,
>    early failures, wall-wort issues, etc). Later versions seem to
>    be fine.
>  - fairly good international support (eg, tones, ringing, supervision)
>    but probably still needs more work for some country standards.
>  - I haven't spent any time testing modem use through the box, so
>    no idea how well it might function.
>
> The voip market-space is not well covered in the one-to-five pstn
> (fxo) line areana. Above approximately four lines, a channel bank
> (with T1 card) is likely to be more cost effective when ongoing
> client support and satisfaction is factored into overall costs.
>
> Hope that helps....
>
> Rich
>
>
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