Answering machine detection

[dspaan]

In the past we tested with Sangoma AMD for vicidial since the general advice was that you could achieve a higher accuracy with Sangoma compared to the inbuilt AMD for Asterisk. I noticed here that Sangoma does not offer that product anymore:

http://www.vicidial.com/?page_id=355

So what is the best way to do AMD right now in 2018?

[vkad]

I want to know too....

[mflorell]

Use humans

But seriously, we are working with a commercial hardware provider to build in compatibility with their CPD product. It operates differently from how Sangoma CPD did(all other options operate differently as well), so it is slow going, but hopefully we'll have a commercial tie-in option available in a few months if testing goes well. If testing doesn't go well, we do have other options we've looked into, but they are not as easy to work with as the company we are currently working with.

[dspaan]

Hey Matt,

That's good to know! What we plan to use it for is debt collection. Asterisk AMD is still 80% accurate right? Even if it's a false positive we can play an audio message about an unpaid invoice so it doesn't matter if it's a false positive, the message is either by a human or a message.

[mflorell]

I would say AMD is 70-80% accurate AT BEST, and that does not include the higher amount of hangups you get when using it because of how long it takes to perform it's analysis.

[lmoreira]

We use call analyse available on Khomp hardware. Combining Khomp's call analyse and native Asterisk's AMD, we are getting great results. Above 95% positive calls from high volume dialing. No impact on call delay because both technology use first 3 secs from answer info for very low false positive or false negative result.

[mflorell]

Thank you very much for your post lmoreira, Could you share how exactly you are using Khomp's CPD solution, what appliance you are using, and how many channels you dial concurrently?

[lmoreira]

Matt,

My setup is:
04 Asterisk Servers with Khomp Channel Driver for total 1240 channels availabe:
40 Khomp EBS GSM 160 (640 GSM Channels)
05 Khomp EBS 4xE1 (600 TDM Channels)
This servers provide Khomp Channels <=> SIP Trunk for VICIDial Cluster (Inbound/Outbound)
On Pure Asterisk servers, I'm dialing using Khomp's CPD feature:

Dial(Khomp/Gcell/${dst}/wait_answer_info:drop_on=message_box>71+answering_machine>72+carrier_message>73+fax>74+unknown>75,,)

So, I have HANGUPCAUSE as 71 on message_box, 72 on answering_machine etc...

On VICIDial Cluster side, about 200 agents running outbound (blended actually) campaign on avg 1:5 Dial Level using AMD with Load Balance: AMD(2000,1000,400,3000,80,50,5,256,500)

So, both CPD running together showed accuracy about 95% so far. I tested only Khomp and only AMD, but anyone couldn't resulted > 80% accuracy.

We are replicating this setup for others customers using Khomp hardware as telephone interface.

[dspaan]

What is Khomp CPD? I searched for it but found nothing.

[lmoreira]

What is Khomp CPD? I searched for it but found nothing.

With 21 years on market, Khomp is a Brazilian company that build carrier grade hardware for tradicional carrier and PBX, and since 2007 has hardware for Asterisk PBX market. Khomp is present on Brazil, Mexico and USA. More about them on http://www.khomp.com.br

We use Khomp EBS with E1 and GSM ports (https://www.khomp.com/en/categoria-de-p ... ies-ebs-3/) on vicidial dialer servers. Those devices allow call answering triage (CPD - Call Progress Detection) that filter out Answer machine, or Carrier Message with about 80% accuracy when used alone. adding Asterisk AMD we push this to 90% or better.

[williamconley]

Those devices allow call answering triage (CPD - Call Progress Detection) that filter out Answer machine, or Carrier Message with about 80% accuracy when used alone. adding Asterisk AMD we push this to 90% or better.

Our last client-sponsored test of Asterisk AMD showed over 90% accuracy (closer to 95%, actually). In which case, what precisely does Khomp do that improves on Asterisk AMD (since you are also using asterisk AMD)?

It is that Khomp can often differentiate between "Answering Machine" and "message box" (actually, I'm not sure there's a difference there ...) or perhaps Fax (which in the US is almost impossible to find by accident these days, lol)

[lmoreira]

Asterisk AMD alone never goes above 80%, actually it has a lot of false negative (hangup on costumer face). Doing AMD and Khomp CPD together, it's reduce false positive (no costumer calls get into callcenter) without increase false negative. So, net result is impressive.

But, sure AMD depends on parameters setup. Could you share your AMD parameters?

[williamconley]

Asterisk AMD alone never goes above 80%, actually it has a lot of false negative (hangup on costumer face). Doing AMD and Khomp CPD together, it's reduce false positive (no costumer calls get into callcenter) without increase false negative. So, net result is impressive.

But, sure AMD depends on parameters setup. Could you share your AMD parameters?

When we tested, we used the Stock settings on the latest Vicibox/Asterisk server available at the time. I think it was 7.0.1. Previously our tests had been with a much older version of Vicibox/Asterisk and gotten 80% or worse. We had to modify the settings quite a bit to rise to 80%. This test was limited to US VoIP telcos.

When we finished the first round of testing, the client decided that Sangoma CPD was no longer even worth discussing. Cost vs return: Adding an entire extra server plus licensing costs for an insignificant increase in reliability (perhaps NO increase, considering how close the results were).

Now that Sangoma no longer sells CPD, it's even less worth discussing. I'd never heard of Khomp before this post.

[garski]

Is the false negative you guys mentioning is the dead air agents are receiving? Whenever we use AMD agents are receiving almost 10% of no answer or no voice sounds on the other line.

[eugeneb]

We have an AMD system which possibly can help you guys to get rid of bunch of machines (false positive - humans) and humans which were considered as machines (false negative - machines). It can be used with Asterisk and Vicidial using EAGI app which swaps the line with your default AMD settings in the dialplan and adds the same AMD variables to the channel. That way you don't need to change any logic in your Asterisk dialplan. Here is a small whitepaper regarding this https://machinedetection.com/docs/AMD_service.pdf. If you want to test it for free just let me know eugeneb@nornov.com.

Regarding dead air / silent calls / ringing calls - if from the network point of view everything is properly configured, then it’s almost always a problem with upstream carriers, especially when you are working with short duration traffic and providers who agreed to pass it, since FAS is still there. And the only ways to eliminate this is a close work with your carriers to exclude bad subcarriers or/and using voice analysis which will check your audio samples in real time and based on noise threshold / ringback tone detection / automatic speech recognition model will tag them as machines, so you can hangup these calls before they will be passed to your agents.

[carpenox]

what settings do you guys use for AMD? im currently using 2000,2,30 but i am still getting dead airs alot