Dialogic IMG - Recording timeslot data to an audio file

Table of Contents

Symptom:

Missing, corrupt, or poor quality audio on Dialogic IMG 1010 Integrated Media Gateway ("IMG 1010") calls between calling and called parties.

Reason for the issue:

Voice path issues on IMG 1010 calls are often due to network issues outside the scope of the IMG 1010; however, without on-site troubleshooting, generally requiring expensive TDM monitoring equipment and an engineer trained in use of such equipment, it is difficult to isolate the root cause to either the network or the IMG 1010.  

Fix / Solution:

Diagnostic commands for making test calls are available in the IMG 1010 CLI and can be accessed using telnet.  These commands enable test calls to individual timeslots - both TDM and VoIP - to be recorded, saved to a file, and then played or analyzed on a PC.  

Notes:

• Only a single timeslot can be recorded at a time

• The recording is limited to one minute in length

• Only one direction of each timeslot - the IMG 1010 receive channel - is recorded.  

So, for example, in a TDM to IP call, recording the TDM timeslot will reveal what the IMG 1010  is receiving from the TDM network in the forward direction, while recording the VoIP timeslot will reveal what the IMG 1010 is receivng from the IP network in the backward direction.   

Normally, the easiest way to gather recordings is to force a test call to come in and go out on specific timeslots.  Then, the arguments for the CLI commands can be determined and applied prior to making each call. 

Timeslot recording on IMG software 10.5.2 and higher:

(instructions for earlier versions below)

• telnet to the IMG in question and enter the advanced debug menu

• From advanced debug menu, type 'k' to find the logical span id for the span that the channel you want to record is on (see example below).

• Find out which channel the call that you want to record is using -OR- block all channels except the channel you want to  record and make a call

• Type the following commands in telnet

z T a ==> span/channel (i.e. 00028,01)
b (starts recording
make test call
b (stops recording)

Here is a example output from the 'k' command:

     PhyID          LogID           Profile         State    Timing
 (comp.if.grp)                      def/act        host/act
 ------------   -------------       -------        --------  ------
   (00.00.00)   0x001c(   28)      E1  /  E1       INS/INS    REF1*
   (00.01.00)   0x001d(   29)      E1  /  E1       INS/INS    REF2
   (00.03.00)   0x001f(   31)      E1  /  E1       INS/INS
   (01.00.00)   0x0000(    0)      E1  /  E1       INS/INS
   (01.01.00)   0x0001(    1)      E1  /  E1       INS/INS
   (01.02.00)   0x0002(    2)      E1  /  E1       INS/LOS
   (01.03.00)   0x0003(    3)      E1  /  E1       INS/LOS

In the first column you see the physical spans. The first 2 digits refer to the group of ports. '00' refers to the Signaling ports. '01' refers to the Bearer ports. The next 2 digits are the port number within the group. So for example '00.01.00' refers to Signaling port 1 and '01.02.00' refers to Bearer port 2.

In the next column you will find the logical ID that you will need for the recording commands above. The example above (00028,01) would record Signaling span 0 channel 1).

Timeslot recording on IMG software 10.5.1 and before

The TDM span and channel can be determined in the corresponding Channel Group within ClientView.  

For VoIP call legs, rather than span and channel, the Module, DSP and channel need to determined.   The easiest way to do this is to take all but one VoIP channel out of service within the IP Bearer object in ClientView.  

Then, with call tracing enabled, a test call is made and notice is taken of the Module, DSP and channel that are displayed for this call in the call trace.  This information is printed in the form [m1.0.1], where in this example, module1, DSP 0, and channel 1 were used.

Once the channels are known, the corresponding timeslots can be determined from the following spreadsheet,  .  This file contains three worksheets: the "Bearer TDM SpanChan" and "Signaling TDM SpanChan" worksheets which map T1 or E1 channels to timeslot and the "Mindspeed" worksheet which maps VoIP Module channels to timeslots. 

Below is an example where Bearer span 3 channel 0 was recorded.  The characters in bold were entered by the user, starting at the Advanced Debug CLI menu:

(******* Make the call, wait for answer, unless you also want to hear ringback. Buffer holds 1 minute ********)

(***** wait for call release or for as long as needed for what you want to record *****)

 
(****** rename the tdm.raw file so it isn’t overwritten next time *****)
 

The tdm.raw file is automatically written to the /home/excelsw/ftpBuilds directory on the Dialogic Gate Control Element Management System (GCEMS)  server.  Once the file is written, it can be downloaded to a PC and played in Goldwave, for example, or any other application that supports a Raw, mu-law, mono format at 8000 hz.

Product List

Dialogic IMG 1010 Integrated Media Gateway
Dialogic MSP 1010 Multi-Services Platform