Asterisk Doesn't Recognize Voicemail in Portuguese

Asterisk Asterisk Support
1

Hi,

Asterisk version: 18.18.1

I have an issue that the Asterisk isn’t recognizing Brazilian voicemail (in Portuguese) which making a situ where lots of voicemail calls are connecting.

Any idea how I can update the AMD module to recognize such voicemails?

Thanks in advance for your help,

Idan

2

The AMD module is purely based on silence and audio. It’s not that intelligent, and provides configuration to tweak its detection.

3

Thanks for the assistance.

After modifying the AMD values,
unfortunately, the situation is still the same, here are the current AMD values:

Initial Silence 1500
Greeting 700
After greeting silence 600
Total analysis time 3000
Minimum word length 80
Between words silence 30
Maximum number of words 3

Attaching an example for a VM call that was connected.

Thank you

4

VM audio file

5

First of all Asterisk’s AMD is NOT perfect.
Secondly you should have at least 4-5 words not 3 on “Maximum words”
These are my settings(if it helps)

initial_silence     =  2500
greeting     =  1500
after_greeting_silence   =  300
total_analysis_time   =  5000
min_word_length    =  120
between_words_silence   =  50
maximum_number_of_words  =  4
silence_threshold   =  384
6

They are reporting false negatives. I thought having too few words would generate false positives.

7

On Thursday 25 April 2024 at 10:13:55, idan.ih2 via Asterisk Community wrote:

I have an issue that the Asterisk isn’t recognizing Brazilian voicemail (in
Portuguese)

Firstly, are you saying that it is not working adequately when presented with
Portuguese, but it does work if it encounters English (or some other
language), or are you simply saying that it’s not working for you (and you
happen to be trying to use it in Portuguese)?

Secondly, if it’s failing in Portuguese but works with another language, can
you try to describe or quantify the difference between them?

For example, I speak on the phone to people in German and in English, and I
would say that if you are calling a business especially, the standard type of
German greeting is much longer than the English equivalent (the Germans state
their own name as well as the name of the organisation, and may use a phrase
along the lines of “how can I help you?”, whereas an English answer might well
be simply the name of the organisation).

You say that the problem is that voicemail calls are connecting, which
suggests that Asterisk is either not hearing the voicemail greeting
sufficiently, or that the greeting is sufficiently short that Asterisk thinks it’s
a human. Have you tried recording the calls (from the moment they get
answered) to see whether the failures are either surprisingly short greetings,
or are particularly quiet etc?

Finally, as FrancoSmash said, Asterisk’s AMD is not perfect. What percentage
of calls which are answered by humans is it correctly connecting, and what
percentage of calls which are answered by a voicemail system is it wrongly
connecting?

Antony.

–
What do you get when you cross a joke with a rhetorical question?

                                               Please reply to the list;
                                                     please *don't* CC me.
8

Thank you very much.

Answering one by one to the questions.

Firstly, are you saying that it is not working adequately when presented with
Portuguese, but it does work if it encounters English (or some other
language), or are you simply saying that it’s not working for you (and you
happen to be trying to use it in Portuguese)? -

The AMD works perfect for me when receiving English VM,
the issue seems to be specificly in Portuguese.

if it’s failing in Portuguese but works with another language, can
you try to describe or quantify the difference between them? -

I would say that the difference between the Portuguese to the English VM is that the Portuguese VM has a shorter and faster greeting and a long time silence after this greeting.

Have you tried recording the calls (from the moment they get
answered) to see whether the failures are either surprisingly short greetings,
or are particularly quiet etc? -

Attaching again a recording for a call that connected with VM in Portuguese:
https://www.dropbox.com/scl/fi/msazhl7ndq9qj9pbc8pd6/voicemail_answer.wav?rlkey=pyzpuo1fmtyqdeqtur6vk808x&st=xvq8ix4j&dl=0

What percentage of calls which are answered by humans is it correctly connecting,
and what percentage of calls which are answered by a voicemail system is it wrongly connecting? -

Around 50% of the calls are connecting with VM (50% connecting to human properly).

9

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