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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hello all,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I hope this is the right place to post this message, I didn’t
see just a list for Zaptel programming.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am working on a project using a Digium 405 T1 card.
I am trying to write an application to talk via the T1 interface to another
piece of equipment.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Very simply, I have set the line configs in zaptel.conf and
then run ztcfg to activate them.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>In my C++ program, I open the data channel -> fd=open(“/dev/zap/1”,O_RDWR).
This application is very similar to a PRI line in that one DS0 functions as a
control channel with a pseudo HDLC communications type link and the other 23
channels get dynamically assigned usage based on incoming and outgoing
calls. Each DS0 is setup to be CLEAR mode, no signaling.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>After opening the device, I check the buffers and change
them to some smaller sizes, make them act immediate, etc.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am able to write my message and see the opposite system
get it and acknowledge it with a message back -> write(fd, buffer, length)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The problem is in getting the data back. I have just a
simple read loop setup to read the data from the buffers that I believe were
setup after the device was opened. This is being done with a simple
read(fd, buffer, length) kind of command. I assume with enough buffers, I
should be able to read the data rapidly enough to not lose anything. I
always get something back buy 1 in 5 times its actually correct (when no
traffic is present, the opposite side is sending 0xFF always so its pretty easy
to know when there is data coming). Most of the time the received data bares
a resemblance to the message that was sent, but certainly isn’t it.
Occasionally the reply message is exactly correct and all is well. Its
almost like the bit alignment is off or something.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Is there something I should be doing differently to reliably
read data back from a channel like this? My next step will be to deal
with the audio channels and the mechanism will be similar. I have looked
at a number of example applications such as fxotune.c and spent some time in
chan_zap.c trying to discern the correct way to read data, but haven’t
yet turned anything up. There are quite a few options to the zaptel API
and I haven’t yet located a good document explaining how to work with it
at the level I need.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Can anybody give me some pointers or point me toward other
information and resources?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Many thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Doug<o:p></o:p></span></font></p>
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