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UC540: Can we limit FX0 call duration?


                  Maybe due to carrier, some of our FX0 calls don't disconnect (the situation occurs most when call originates from outside and outside hangs up first; especially more likely when the outside caller was on hold or in conference and then hangs up). Anyway tried lots of stuff - looks like the carrier Cablevision/Lightpath doesn't always forward supervisory disconnect.

We wanted to limit call times. We never go over; for example, 5 hours.  So if we limit call times to 5 hours then at least the FX0 lines would clear over night.

Is there a command to limit FX0 call time? Both directions is fine as long as we eventually get a disconnect.


Joe Galea

8 Replies 8

Leo Salcie Tejeda
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There's not such feature in CME. You will need a tcl script to disconnect The call. I recommend you this link:

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Thank you Leo for recommending my work. However in a case like OP is described, it is enough to configure tone-based disconnect supervision to avoid stuck lines.


Even though the system does not hang up, yes, the FX0 we eventually get a rapid beep - the rapid beep just continues and continues.   I thought that the helpline tried to disconnect based on the rapid beep tone but our rapid beep had 4 peaks not two peaks.  The helpline was able to get a disconnect based on the beeps found over seas (two peaks) but not from our carrier (four peaks).  

I can't seem to attach the associated file that can be played using the Audacity application. The Audacity application shows 4 peaks.

Can you use tone-based disconnect supervision if the rapid beep has 4 peaks?


Yes, tone-based disconnect supervision can be used with any pattern, as it is fully configurable.


Capturing the audio and using the Audacity application, the helpline and I believed that the repeating 4 frequencies are 1400, 2060, 2453 and 2600 Hz, it’s an information to the user that phone’s handset is left off hook.

I received this from the helpline:

"We tried to configure and use this tone as disconnect tone in order to make call disconnection, however because it is consisted of 4 different frequencies, it’s not being possible to configure that. If that tone would have only 2 frequencies, we would be able to prepare disconnect tone for it."

I very much appreciate the helpline but does this particular response from the helpline make sense? [Actually, the repeating 4 frequency peaks may be 1400, 2060, 2450 and 2600.]

Thanks again,


That is called howler tone. You can try configuring the two prevalent frequencies, but I'm not sure there is any.


Do you know the CLI Commands in our case?  After about 40seconds of silence we get the North American Off-Hook Tone which is 1400,2060,2450, 2600; cadence .01sec on, .01sec off.  There is about 40 to 50 secounds of silience on that particular line before the tone starts.


Cisco IOS Software, UC500 Software (UC500-ADVIPSERVICESK9-M), Version 15.1(4)M4b, CIBU Special
Small Business Support:
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Fri 18-May-12 15:06 by CIBU

ROM: System Bootstrap, Version 12.4(24r)SB, RELEASE SOFTWARE (fc1)

UC_540 uptime is 14 weeks, 4 days, 22 hours, 47 minutes
System returned to ROM by power-on
System restarted at 10:28:01 EST Wed Jan 9 2013
System image file is "flash:uc500-advipservicesk9-mz.151-4.M4b"


Thank you,


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