[asterisk-users] USB dahdi fxo ?

Greg Troxel gdt at lexort.com
Sat Dec 14 10:29:46 CST 2019

sean darcy <seandarcy2 at gmail.com> writes:

>> There is also the ObiHai OBi202 with an OBiLine, which provides an FXO
>> port remoted over SIP.  (I am not sure if this is discontinued.)
> "FXO port remoted over SIP"?
> I have an analog phone system. I can use the obi202 to connect the
> system to asterisk ? That is, the 202 will connect a outgoing call
> from one of its phone ports to asterisk, and connect an incoming call
> from asterisk to that same phone port ?

The obi202 is sort of a mini pbx itself.  It has 4 slots for programming
SIP service providers (ITSP and SP, split, but four of each).  Then
there are call routing strings you can program to tell it what to do.

On mine, I have three Service Providers configured for SIP, all with
ITSP profile A.  Basically, PH (first FXS) has a sip login to asterisk
via SP2, and a "primary service" of the SP2.  So while I can dial **N to
make it do other things (an obi thing), if I pick it up and dial my
hello world extension it works.  PH2 is similar but on SP3.

Then, I have another sip login on SP1, for the FXO port, and an inbound
call route to sp1(NNNNNNNNNN) - just to have a dialplan destination for
incoming calls.  When the POTS line rings, asterisk gets an INVITE and
can route it back out to PH, or whatever.  I have set the 'spoof
callerid" flag on the obi, so that the callerid from POTS is passed to
asterisk as the origin.

On SP1, I have inbound call route set to "li", so that calls from
asterisk go out the POTS line.

I asked on the list earlier, I think, about the wisdom of separate SIP
logins to logically separate these, vs trying to mulitplex based on
digitstrings.  I concluded that especially given that I had no need for
more service providers in the obi, that I might as well assign SP1/2/3
to LI/PH/PH2, and be able to tell the obi "calls arriving on SP3 just go
to ph2" rather than having to sort inbound calls by destination (which I
suspect is doable).  There is more complexity already inherent in the
system than seems fun, so I am tending to reduce it when it doesn't cost
me funtionality.

I have encountered the dreaded spurious touch tone problem, in a way
where they keep going.  I believe this is due to confusion about
signaling mode and talk-off, and have set the obi explicitly to RFC2833.
That seems to work, but I'm not sure.

> BTW, the 202 is one sale today at Amazon !

Keep in mind that the 202 provides two FXS ports.  You need the OBiLINE
also (plugs into USB port on 202) to get an FXO port.

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