Dialogic Voice Cards - Recording TDM streams for fax troubleshooting - audiorec
Introduction
The audiorec utility was written as a means of recording the input and/or output TDM streams of fax sessions. However, it has no knowledge of fax and therefore can be used to capture any voice data on both the input and/or output streams. This article describes the use of audiorec for fax troubleshooting.
Some fax issues can be resolved by reviewing the ctdaemon log. In other cases, it may be advantageous to process the audio recording from a fax session.
The audiorec utility reduces the complexity of capturing recordings; without it, it would be necessary to make the proper switching connections between the timeslots being used for the fax session and the timeslots to be used for the recording, then run one or more instances of ctatest and initiate the recording within each instance of ctatest.
audiorec creates the switched connections between the trunk voice timeslots which are to be recorded and the available DSP voice timeslots used to capture the audio data. Therefore, before running audiorec, the user must identify which set of sequential DSP voice timeslots will be used for recording. If the user is recording both the input and output streams, they must allow for two available DSP voice timeslots for each timeslot to be recorded.
Windows, Linux and Sparc Solaris versions of audiorec are available for download in a single zip-file .
Running audiorec
Here is the help you get from audiorec when running "audiorec -h":
Usage: audiorec [-b #] [-s #:#] [-r timeslot] [-f filename] [-z encoding] [-I | -O]
where -b # is the board number (default 0),
-c # is the number of timeslots to record (default=1)
-f base filename for recordings. Default: 'recording'
-r starting target Voice DSP timeslot used to record(default=0)
-s #:# is the starting stream and timeslot (default 0:0) to be recorded
-z encoding type for recording file (default=10 (mulaw))
-I don't record input
-O don't record outputExample:
audiorec -r 192 -s 0:96 -f audiorec -c 5
This records the input and output streams for 5 timeslots starting at timeslot 0:96. Recording is done starting at DSP voice timeslot 65:192
by switching the input streams to the even timeslots and switching the output streams to the odd timeslots. Timeslots 65:{192..201}
need to be available so that audiorec can create the switched connections between the trunk voice timeslots (0/1:{96..100}) and
these voice DSP timeslots. audiorec will record the data switched into the DSP voice timeslots.
For this example the switching will be (trunk voice input/output --> DSP voice input) :
0:96-->65:192, 1:96-->65:193
0:97-->65:194, 1:97-->65:195
0:98-->65:196, 1:97-->65:197
0:99-->65:198, 1:97-->65:199
0:100-->65:200, 1:97→65:201
and will create files audiorec-input-96.wav, audiorec-output-96.wav, audiorec-input-97.wav, audiorec-output-97.wav, etc.
When you launch audiorec using the above command, you will see:
C:\jimsfax>audiorec -r 192 -s 0:96 -f audiorec -c 5
Recording 0:96 to timeslot 192 to file audiorec-input-96.wav
Recording 1:96 to timeslot 193 to file audiorec-output-96.wav
Recording 0:97 to timeslot 194 to file audiorec-input-97.wav
Recording 1:97 to timeslot 195 to file audiorec-output-97.wav
Recording 0:98 to timeslot 196 to file audiorec-input-98.wav
Recording 1:98 to timeslot 197 to file audiorec-output-98.wav
Recording 0:99 to timeslot 198 to file audiorec-input-99.wav
Recording 1:99 to timeslot 199 to file audiorec-output-99.wav
Recording 0:100 to timeslot 200 to file audiorec-input-100.wav
Recording 1:100 to timeslot 201 to file audiorec-output-100.wav
Type 'h' for help
Type 'q' to stop recording and exitWorking with Recordings
Once you have captured the audio recordings of the fax session, a 3rd party Windows-only utility called 'faxintercept' can be used to process these recordings.
Note: faxintercept is not a Dialogic utility; at the time this article was prepared, it was available from the Downloads section of the website of Miller Engineering Services, Inc (MESi) by selecting the 'Fax Intercept Evaluatation' link. (Dialogic is not responsible for the content of this external website).
faxintercept takes as input a mu-law WAV file and creates the TIFF output as well as a summary log and a detailed buflog.txt file. Here is an example of a 6-page fax sent from a Dialogic® AG 2000 PCI Media Board (analog) to a Dialogic® CG 6060 PCI Media Board (digital) and captured into the file tiff.wav. audiorec was used to capture the audio from the CG 6060.
faxintercept tiff.wav 6pages.tif 6pages.summary
Here is the what the 'summary' file contains where the Initiator sent the fax:
Since this fax was sent from an analog board, the recording captured both the transmitting (Initiator) and receiving (Responder) side of the fax due to echo. This means that audiorec captured the fax image data sent by the AG 2000 and also captured the the T.30 responses it sent since they were echoed from the AG 2000.
In an all digital connection, you would have to run faxintercept on both the input and output recordings. faxintercept will produce a TIFF file for the recording that contained the fax image data but will only produce the 'summary' file for the receiver of the fax.
Product List
- audiorec works with the following CompactPCI and PCI boards:
Dialogic CG 6x00 CompactPCI Media Board
Dialogic CG 6x6x Media Board