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<div class="moz-cite-prefix">Hello Scott,<br>
<br>
Thanks for your reply and clarity given by adding needful
information to call flow.<br>
<br>
If I understand correctly, there are three dependencies to
implement complete real time FoIP using T.38 (over both PSTN and
VoIP). 1) Asterisk 2) T.38 capable fax modem software 3) VoIP
gateway (VoIP provider) with T.38 support.<br>
<br>
Please correct me, If I am wrong.<br>
<br>
Now, Can I use "opalvoip" as T.38 capable fax modem software in
our flow? Can I add "opalvoip" as a plugin to "Asterisk" (like
SpandDSP)?<br>
<br>
I look forward to hearing from you.<br>
<br>
Thank you.<br>
<br>
Regards,<br>
Chandra.<br>
<br>
<br>
On 1/9/2014 8:39 PM, Scott Griepentrog wrote:<br>
</div>
<blockquote
cite="mid:CACrpESaC7L+6X1W0DON1XvS9ScWVpFf_6bDMKMmk8BfD5GTwvQ@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default" style="color:rgb(102,0,0)">To add
some details to your call flow for clarity, I would write it
as:</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">
Sending FAX machine (T.30) ==POTS==> Local CO
==PRI/G711/T.30==> (PSTN) ==> VoIP Gateway with T.38
support ==IP/SIP/RTP/T.38==> (INTERNET) ==> Asterisk
(with T.38 capable fax modem software) => .TIFF file</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">I'm using
==protocol/stack==> to indicate the signalling/media
methods, and (network) to indicate a large complicated routing
network that isn't changing the datastream.</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">In this
diagram, note that:</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">
1) POTS Analog to Digital (G711) conversion is done by the
CO's SLIC</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">2) The
VoIP gateway when using T.38 does the G711/T.30 "Modem"
conversion to T.38. A way to understand this is that it's
like the serial port on the back of the old style modems, only
the data is carried in RTP packets and called T.38. Portions
of the T.30 decoding still have to be done by a software
program inside or alongside Asterisk.</div>
<div class="gmail_default" style="color:rgb(102,0,0)"><br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">The same
sequence where T.38 is not used - just a conventional T.30
fax over G711:</div>
<div class="gmail_default" style="color:rgb(102,0,0)">
<br>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">
<div class="gmail_default">Sending FAX machine (T.30)
==POTS==> Local CO ==PRI/G711/T.30==> (PSTN) ==>
VoIP Gateway ==IP/SIP/RTP/G711/T.30 ==> (INTERNET)
==> Asterisk (with fax modem software) => .TIFF file</div>
<div><br>
</div>
<div>Note that the "asterisk fax modem software" has to
include the entire T.30 stack including all the V.xx
protocols, plus T.38 if needed.</div>
</div>
<div class="gmail_default" style="color:rgb(102,0,0)">
<br>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Thu, Jan 9, 2014 at 5:38 AM,
Chandramouli P <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:crazymoonboy@yahoo.com" target="_blank">crazymoonboy@yahoo.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF"> Hi,<br>
<br>
I have some basis queries about the internal flow
(conversion) and architecture of FoIP. Please note that I
have done enough research on Internet to clarify my
queries. But, I didn't get proper information. I thought
of sending you guys an email to clarify my queries:<br>
<br>
I want to implement a real time fax service with Asterisk
(FoIP with Asterisk) using T38 protocol. For this, first I
would like to clear with the basic internal flow of
sending fax over IP.<br>
<br>
<b>Send Fax -> Fax Modem -> Asterisk -> Receive
Fax </b><br>
<br>
1) Please correct me, If I am wrong with the above flow.<br>
2) Can we consider "opalvoip" as Fax modem?<br>
3) Can we consider "SpanDSP" as Fax modem?<br>
4) Can we consider "HylaFax" as Fax modem?<br>
5) Can we consider "Fax Modem" as "T38 Gateway" in the
above flow? If not, where I need to put T38 Gateway in the
above flow? Can you please rewrite the flow? <br>
6) Can I use "opalvoip" as Fax modem in the above flow?<br>
7) T38 Gateway contains T38 Receiver and T38 Sender. Is it
correct?<br>
<br>
Hence request you to find some time to reply and also
reply in inline.<br>
<br>
I look forward to hearing from you.<br>
<br>
Thanks in advance.<br>
<br>
Regards,<br>
Chandra. </div>
<br>
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