Adhearsion: Call Recordings

Previously, I mentioned that Power Home Remodeling Group makes around 48,000 calls per day. While a lot of those are no answers or answering machines we still make contact with a lot of people every day. We record those calls. If we don’t reach someone, we simply record whether or not we left a message on their machine, or if it was truly a no-answer. When we do reach someone and talk to them, Adhearsion records it. We do inform the person that we are recoding the call. When a call hangs up, our Talkbox Adhearsion application sends an API call to our main Nitro application. The path of the audio recording and the home it’s linked to are included so Nitro can put them together into that home’s overall communication history.

Adhearsion: Confirming Appointments

At PowerHRG, appointments initially made with a live person. This could be at an event, some retailer where we have an area set up, or an employee who knocks on doors. An appointment will get scheduled for a remodeling consultant to visit the homeowner. At the same time, we’ll also get any written permission we need in order to contact the homeowner. A confirmation email is sent as an appointment reminder. Remember, it’s not legal to call a cell phone without prior written consent. Since many people only have cell phones, we wouldn’t be able to call them otherwise. You can review more about the rules for automating phone calls in my previous post.

Why we confirm all appointments

Life happens. We prefer to find out if the homeowner can’t make the appointment before we send somone out to see them. In our experience, calling to confirm as close to the appointment time as we can is the most accurate way to ensure the appointment can be met.

Automating the call

Talkbox, our Adhearsion server, is constantly looking for upcoming appointments during business hours. When it detects any unconfirmed appointments coming up within the next few hours, it will make sure we have agents signed in to take calls and then initiate calls to those homeowners. Confirmation agents are signed in and waiting in a their own private audio conference room setup by Talkbox. This way the agent is instantly ready to talk. Otherwise, we waste time with Talkbox attempting to negotiate the call. When the homeowner answers the phone, Talkbox bridges the call with an available agent’s conference room. The homeowner’s name and number appears on the agent’s desk phone. The agent can see instantly who they are talking with. At the same time as the call is connected, Talkbox sends a message to Nitro to refresh the agent’s application window with the homeowner’s appointment info. This could take a few seconds so the desk phone display is useful because it’s quicker and offers confirmation that the information on the screen is the for the correct homeowner.

What happens when we can’t reach the homeowner

We obviously can’t reach the homeowner directly one hundred percent of the time.
  • No answer: If the call isn’t answered at all, Talkbox will re-queue the appointment to call back in another twenty minutes before calling them back. We do this until about thirty minutes past the originally scheduled appointment time.
  • Voicemail: Talkbox will leave an automated message asking the homeowner to call someone back to confirm their appointment. Alternate numbers will be called as with a no answer.
If we simply can’t reach the homeowner at all to confirm the appointment, we schedule a call for the next day to reschedule for another time.

How does Talkbox know it reached a person or a machine?

There are a few behaviors that can be key in an application detecting whether a live person or an answering machine is answering a call. Nothing is one hundred percent accurate.
  • People typically answer the phone by saying something right away. So if there’s a delay in hearing any audio at all there’s a good chance it’s an answering machine.
  • Most people answer the phone by saying “Hello”. Answering machines tend to respond with a sentence or two at least. So the length of the initial greeting is another indicator.
Adhearsion has answering machine detection with configurable settings to adjust for the specific needs of a business.

About Automating Outgoing Phone Calls

You can’t just load up a bunch of phone numbers into a database and start calling them. There are laws. Don’t break them. Our automated outbound calls fall into three categories which I’ll cover in follow up posts. For now, I wanted to touch on some information anyone should know about before hooking up an application to make phone calls. Particularly when it comes to telemarketing and autodialed calls.

Federal Regulations

Back in 1991, the Telephone Consumer Protection Act was passed. It restricts phone solicitations and the use of automated dialing. It covers SMS messaging and faxing in addition to normal voice calls. Here are some of the primary restrictions. There are more, so don’t take this as a complete list.
  • Don’t call anyone before 8am or after 9pm. If you do business across time zones, you need to deal with that.
  • You need to maintain you’re own do not call list. If someone asks to be put on it, add their number. You have to honor it for at least five years.
  • Honor the National Do Not Call Registry. See section below
  • Tell people who you are and your phone number or address.
  • Don’t call emergency lines or anyone who’d be charged for your phone call.
  • Don’t call cell phones without prior written consent. That’s right, you’re not allowed to make unsolicited calls to cell phones. Period.
  • As I said above, there are a lot of other rules.
If you break any of the above rules, you can get taken to court.

National Do Not Call Registry

The Do Not Call Registry allows anyone to register their phone number. Telemarketers are never supposed to call any registered number unless the person has given you permission. You can register to access this database, either via an API or as a downloadable list at the Do Not Call Registry Telemarketer site.

Common Courtesy

Not all calls are unsolicited calls. You may just being trying to confirm a scheduled appointment. Regardless, you want to be courteous to the people you call.
  • Don’t make excessive calls.
  • If you get voicemail, and leave a message, give the person some time to respond. Don’t call back every five minutes until you reach someone.
  • If you talk to someone who requests a call back in three months, you should respect their request. Leave them alone for those three months.

More information

What is a Robocall?

Robocalls include automated phone calls made using autodialers. This includes calls that only contain pre-recorded messages and those where you speak to a live person.

What is an Autodialer?

Any type of equipment or computer software that dials phone numbers without human intervention.

How can you determine if a phone number is a landline or a cell phone?

A variety of sources exist to assist businesses and telemarketers to tell if a number is a mobile number. For example, NeuStar, as the North American Numbering Plan Administrator, the National Pooling Administrator, and the LNP Administrator, makes information available for the purpose of identifying phone numbers assigned to wireless carriers.

Adhearsion: Click to Call

One of the most basic things you can do when you tie an application in with your phone system is implement click-to-call. You click a phone number on your web page, or within your application. It connects you to that phone number.

What the user experiences

From the user’s perspective within our application it goes down like this:
  1. Click a phone number link in the web page.
  2. In a few seconds your phone extension will ring.
  3. You pick it up and you’ll hear your phone number being dialed.
From that point on it’s just a normal phone conversation. You just didn’t have to dial the phone yourself.

What happens behind-the-scenes

You’re logged in, so the application (Nitro for us) knows who you are and you’re phone extension. This is what happens from the application’s point of view:
  1. It shoots an API call with the user info and phone number to our Talkbox (i.e. Adhearsion) server.
  2. The phone call is initated with Asterisk.
  3. The user’s phone extension is rung.
  4. As soon as the user picks it up, the outgoing phone call is initated.
That’s about it. All this assumes is that we have the user’s extension number stored properly in the database. This obviously isn’t much of a benefit if you’re away from your desk. It does alleviate issues with mis-dialed numbers and makes it a little less of a hassle for dialing when it’s an option.

Our Adhearsion Environment

I mentioned in my last post that I’ve been working mostly for Power Home Remodeling Group for a while. Primarily on the app that runs their business. We call it Nitro. Initially, I plan to focus on our integration with Adhearsion. I’ll keep things to a functional level rather than getting too in-depth technically. If you’d like more technical details about a topic leave a comment. I can get into specifics if there’s enough interest. The simple reason is that it takes longer to write a post with code examples. I think there’s sufficient value in describing what’s possible at a business level.


Our production environment lives on a number of virtual servers hosted in our corporate hosting center. Our current setup includes five web servers, five transaction servers and a single server which runs Asterisk and Adhearsion. The transaction servers run cron jobs, background processes and our call loop which feeds our phone system with numbers to be called. More on that in a future post. On our Asterisk/Adhearsion server we also have a separate application running on it we call Talkbox. This is a custom Adhearsion app with PowerHRG’s business logic. It runs as a service and communicates back and forth with our main Nitro application via API calls.

So what does Power Home Remodeling Group do?

PowerHRG sells windows, siding, doors, roofing and a few other products. We make a lot of phone calls to do that. The majority are appointment confirmations and marketing calls. Around 48,000 outgoing calls every day. Yes. All with a single Asterisk/Adhearsion server.


Adhearsion is described as an
open-source voice application development framework.
It actually does a bit more. We’ve tied it into our LDAP server so our phone systems and applications use the same info and security. Adhearsion can even integrate over XMPP (Jabber) to support stuff like instant messaging. In my next post, I’ll start talking about some of our specific uses of Adhearsion. Stay tuned.