How to increase the number of seconds the dialer can record silence

Technote (troubleshooting)


Customer has a B2B survey where interviewers can be put on hold for a while, but the dialer stops recording after 60 seconds.


The default value of the "sil" parameter, defined in the dialer.ini file is 60 seconds, that is why the dialer stops recording after 60 seconds.


Windows and Linux dialers

Diagnosing the problem

The legenda in the dialer.ini file says:
sil:60.0 Max silence (secs, max 65.535, 0 for unlimited), default 60.0
Silence is detected by the DSP itself. The 65535ms limit is a restriction in the DSP firmware

Resolving the problem

To allow >65.5 seconds silence in recordings, the customer should set sil=0 (don't stop upon silence), such that the recording continues until stopped by the application or when the call ends.
The sil= limit is only there to avoid flooding the disk, say, if a call is answered by a silent machine (a voice box without an announcement), but the interviewer fails to recognize that he has a connected call (even though his monitor now shows the call outcome screen). If under these circumstances the interviewer gives up waiting and leaves the booth for the day without signing off and without putting the phone on-hook, you will eventually have a big phone bill and a full disk. Setting sil>0 solves the latter, not the former. If the interviewers are trained to sign-off when they leave, then none of this will happen, and you don't need the sil timer.

Document information

More support for:

SPSS Data Collection Heritage

Software version:


Operating system(s):

Linux, Windows

Reference #:


Modified date:


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