911 Background and Basics

Emergency calling is a part of every SfB deployment I’m part of, and yet it seems to be an area that most people don’t have a good background on. This makes understanding capabilities and limitations a bit of a challenge. Over the next handful of posts, I’ll cover the background behind 911, some basics on how 911 works with boring analog home phones, traditional TDM business phones, mobiles, and then we’ll through SfB into the mix.

Let’s start by talking about an analog home phone, or a single business analog line like for a fax machine. When you sign up with your telco for this line, you provide them with an address for service, and that address is where the line terminates. There is no option for you to move the line, so the telco can build a large list of names, addresses, and phone numbers, and be very confident in the static nature of that list, and thus its accuracy.

I won’t address MLTS, or Multi-Line Telephone Systems, aka a traditional PBX connected to the telco via PRIs. For the purposes of how 911 works, they’re largely treated as a collection of virtual analog lines, and there’s not much different about how that’s handled – you assign locations to numbers, and the telco enters that information into their databases.

In a 911 (vs e911) scenario, when you call 911, no address or telephone number information is provided. The caller has to provide this information. Once your location is established, that operator has to transfer your call to the correct PSAP – Public Safety Answering Point – local to you. That’s never fun when you’re in distress, so in most regions of North America we’ve progressed to e911 – e for enhanced – where your information can be automatically passed on.

With e911, the address that you provided to the telco is put into a database along with your phone number. Now when you call 911, the telco can use this information to route you to the correct PSAP, and the operator at the PSAP can see your information on their screen. As a safety measure, they’ll almost always verify your address with you. When your number is automatically display at the PSAP, it’s referred to as the ANI, or Automatic Number Identification. . The PSAP then takes your ANI and performs a database lookup to retrieve the civic address. This is called the ALI, or Automatic Location Identification.

Though very similar, ANI and Caller ID aren’t the same thing. Caller ID is for customers and can be blocked. ANI is for telco use. You can block your Caller ID, you cannot block ANI.

This system works very well with static analog systems, where a pair of wires physically terminates at the address you provided. It falls apart completely when the phone becomes mobile, either VoIP or cellular. In my next post, we’ll consider how cellular/mobile e911 can work (and fail!) and why the pizza company knows more about your location than your PSAP.

Main Number Handling: Response Groups, pt 6 – Interactive Response Groups

We’ve setup and explored almost all of the functionality that Response Groups have to offer. The remaining part is Interactive Response Groups. You may know these as IVR, or Interactive Voice Response, or call trees.

Interactive Response Groups allows you to play a message, and have the caller press a key or say a response, in order to direct them to the most appropriate Queue.

Configuration Differences vs Hunt Groups

In comparison to Hunt Groups only Step 7 in the configuration process differs. In Step 7 for Hunt Groups, you simple select a Queue to send the call to. For Interactive Response Groups you need to specify, at a minimum:

  • A welcome message, either icky text-to-speech or a recording
  • Two options for your callers to choose from, along with Queues to deliver them to

With the response details collapsed, Step 7 looks like this

Step 7 collapsed


Note that Responses 3 and 4 are optional, use the checkbox to enable them.

The configuration options within each Response are the same. First, you specify what response from your caller corresponds to this Response option:

Response 1

You can configure keypresses of 0-9, *, #, or nothing. You can also provide voice-recognized words for your callers to use. Note that a blank keypress means your callers must use a voice response. Given that crummy cell phone calls can interfere with speech recognition, you should always include a keypress option. For voice recognition options, you can include multiple responses separated by a comma. For example:

Response 1 multianswer

If you want to offer more level of questions, you can choose to ask another question instead of sending a call to a queue

 Full Response Expand

Here again, you must provide at least two options, and you have an option to provide up to four.

With the four “level one” options, and then 4 more “level 2” options, you can ask you callers a maximum of two questions, and direct them to 16 different Queues based on their response. In my experience, that’s more than sufficient to prevent annoying your callers, but to also get them to the right agent. If you need more options, you can use PowerShell to configure more, Anthony Caragol provides a great overview of that process. That doesn’t look like fun, and if you build a mess and hand it off to a co-worker, I’m pretty confident you won’t be getting any Christmas cards from them. Worse would be if you build a mess, and then have to come back and change it yourself in several months.

You might also consider Call Flow Manager which provides a much better interface and allows for more options.

However, be aware that if you configure a Response Group that has more options than your GUI of choice, you must resort to Powershell. Planning your IVR carefully means happier callers, and happier you. If you find yourself being forced into PowerShell to manage your IVR Response Groups, I’d say that’s a pretty strong indicator that you should have a look at contact center software.

When you’re configuring multiple layers, note that you don’t have to have two layers for every option. For example, if your first level question is “Sales or Support”, you can send calls for the sales team off to the Sales Queue, and then ask  a 2nd level question for those who chose Support.

There is a lot of flexibility in the Interactive portion of Response Groups versus a standard Hunt Group. Plan carefully to keep yourself happy when you to support what you’ve built!