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Failed PSTN Outgoing Calls - Busy Signal

Started by tom827, March 24, 2013, 12:03:11 PM

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tom827

I have my Obi110 setup to use the PSTN line for outgoing calls by default. About 25%-50% of the time, the outgoing calls fail to go through, and I get a busy signal from my phone. The Obi110 status page shows a successful outgoing call to the right number.

Is there something I can change on the "Port Settings" to make this work more reliably?

Shale

You might try increasing these:
Quote
DialDelay
   
Delay in milliseconds before dialing out the first digit to the PSTN line after the OBi takes the LINE port hardware to the Off-Hook state. This is a simple way to allow the PSTN company time to get ready to receive DTMF signals from the OBi without having the OBi monitor dial tone from the PSTN company
500

DialDigitOnTime
   
Duration in milliseconds of each digit to dial out on the PSTN line
   200

DialDigitOffTime
   
Interdigit time in milliseconds when dialing a number on the PSTN line
   
200
I don't use PSTN myself, but I wonder if these might help.

ianobi

I agree with shale. The last time this question came up increasing DialDelay to 1000 cured the problem. 1000 = 1 second.


tom827

Quote from: ianobi on March 24, 2013, 12:30:30 PM
I agree with shale. The last time this question came up increasing DialDelay to 1000 cured the problem. 1000 = 1 second.



Quote from: Shale on March 24, 2013, 12:25:54 PM
You might try increasing these:
Quote
DialDelay
   
Delay in milliseconds before dialing out the first digit to the PSTN line after the OBi takes the LINE port hardware to the Off-Hook state. This is a simple way to allow the PSTN company time to get ready to receive DTMF signals from the OBi without having the OBi monitor dial tone from the PSTN company
500

DialDigitOnTime
   
Duration in milliseconds of each digit to dial out on the PSTN line
   200

DialDigitOffTime
   
Interdigit time in milliseconds when dialing a number on the PSTN line
   
200
I don't use PSTN myself, but I wonder if these might help.

This seems to have fixed it. I set DialDelay to 1000, and it worked for a few tests. I reduced DialDigitOnTime and DialDigitOffTime to 150, and DialDelay to 850 in an attempt to reduce the calling delay. I'll keep testing it for a few days, and make sure it works permanently, but at least initially it appears that this helped.

ianobi

DialDelay is probably the most important factor here. If you are a long way from the telco telephone exchange, then the line needs to be seized by the OBi, telco returns dial tone and then a short time to allow the physical line to become stable is useful.

If DialDelay is OK, then I have found that DialDigitOnTime and DialDigitOffTime can be reliable at 80ms.

ProfTech

That is a great piece of information, ianobi! Thanks. I have been dealing with this for 2 years. My daughter recently switched to UVerse and was getting weird, random results when dialing out the PSTN. Sometimes busy same as the OP, sometimes a weird message with a ton of static, and sometimes the call would go through. I was playing with the DTMF on/off times but it hadn't occurred to me to extend the dial delay. I was able to put the DTMF timers back to default after changing the dial delay to 1000 which of course gives the user a more warm and fuzzy feeling.  ;)