Author Topic: A way to check dial speed using asterisk  (Read 126 times)

Offline markosjal

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A way to check dial speed using asterisk
« on: March 07, 2018, 09:02:56 PM »
Here is how I check dial speed. This is probably more accurate than what the telco used back in the day.

First what you need to do it.

asterisk , or other IP PBX capable of recording to a WAV or other file format.
ATA to connect the phone to asterisk (need not be pulse compatible if we use a second phone to dial)
Audacity (free download for all platforms)
If not on the same machine a way to get files from one to the other . I used filezilla and copied over a LAN.

in asterisk make a dial plan:

exten => 111,1,Answer
exten => 111,2,Wait(2)
exten => 111,3,Record(asterisk-recording%d.wav)
exten => 111,4,Hangup

from asterisk console type:
core reload

We use 111 to dial in so a dial with incorrect speed will still reach the recording.

once dialed we then will hear a beep and asterisk will record. DO NOT test a few random digits , be sure to test 0 and 2 as sometimes dial speed issues relate to the number dialed and how far the spring gets wound.

now hang up

Now we copy the recording from the asterisk box to a computer running audacity
the recorded files at /var/lib/asterisk/sounds to local computer wherever you like.

Open the copied file in audacity

once open at the bottom of the screen select the tick box that says "length"

We select the magnifying glass at top of screen so we may more accurately select from peak to peak

Now we select the tool from the top that looks like an "I" and highlight from one dial pulse peak to the next. you may see echos, reflections or harmonics such as in the image here. Ignore those.  When you dialed 0 you will see 10 pulses be sure to check the duration of the first to second pulse as well as scrolling forward then to the ninth to tenth pulse.

the duration will show at bottom of Audacity screen. You want this as close to .100 as possible for all digits dialed.

Be sure to test as many combinations as possible and always testing 0.
« Last Edit: March 09, 2018, 10:19:32 AM by markosjal »
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