Users type extensions too fast

Hi There!

Some of my younger users (especially those who game on mobiles) have a problem with dialing
the extensions.

If they dial the digits of the extensions too fast the system bugs…

I use standard waitexten to process the buttons pushed.

If they dial the digits with ta least (around) 0.6 seconds between the digits, it works just fine.
Any faster than this and the asterisk cannot take it.

Is there any way to make the data processing of asterisk?

Yours Sincererly

Laszlo Balogh

If this is dahdi, there are parameters, in chan_dahdi.conf, although they may increase talk-off (treating speech as DTMF). I think the situation for SIP is probably dictated by the phones.

; If you are having trouble with DTMF detection, you can relax the DTMF ; detection parameters. Relaxing them may make the DTMF detector more likely ; to have "talkoff" where DTMF is detected when it shouldn't be. ; ;relaxdtmf=yes

600ms seems much too long, as autodiallers will dial faster than that.

These are the parameters normally used for inband DTMF, although one would normally not use inband signalling with VoIP:

[code]/* Basic DTMF specs:

  • Minimum tone on = 40ms
  • Minimum tone off = 50ms
  • Maximum digit rate = 10 per second
  • Normal twist <= 8dB accepted
  • Reverse twist <= 4dB accepted
  • S/N >= 15dB will detect OK
  • Attenuation <= 26dB will detect OK
  • Frequency tolerance ± 1.5% will detect, ±3.5% will reject


The problem occurs, when the users dial in from their mobile phones through a gsm adapter card.

It is an o***vox one, it uses some chan_extra driver.

Should I inquire about this on the manufacturer support forums?

THX 4 the tips!

Laszlo Balogh

The limitation may well be in the GSM network. GSM networks always send DTMF out of band as the GSM codec is not capable of handling such non-voice-like signals accurately.

Asterisk has options for logging DTMF events.