SIP Configuration Guide

Fonolo is compatible with all major call center platform vendors (Avaya, Five9, Genesys, Cisco, etc.). Fonolo has several different options for connecting to your call center, including via a SIP connection over the internet.

This guide will outline the necessary steps, and information that we require, to set up a SIP connection between your phone system and the Fonolo Cloud – you can return the specific information required for your Fonolo deployment using the SIP Setup Form below:

It is important to note that the exact configurations required will vary from company to company. For more information or assistance in setting up a SIP connection to Fonolo, please email Fonolo Support, or call 1.855.366.2500.

1. Offer Message in Queue

The Fonolo Call-Back process begins with an offer message being played to the Client while they are waiting on hold. Each queue that you will be offering call-backs on should be configured to play an offer message, with a DTMF response (typically DTMF 1) initiating a transfer of the call to a Fonolo SIP Extension to begin the opt-in process. Offer messages typically say something like, “If you’d like to get a call-back rather than waiting on hold, press one now.”

You will need to configure:

  • An offer message to be played on each queue (post-IVR) offering a call-back
  • A DTMF response for an opt-in triggering a transfer of the call to a Fonolo SIP Extension

The initial offer message will need to be put in place in your existing messaging, based on whatever business rules are appropriate. Fonolo can offer some suggestions on frequency and threshold for making this offer, based on the success of some of our other customers.

2. SIP Extension Programming

When connecting to Fonolo via a SIP connection, we require one SIP Extension per queue that you will be offering Call-Backs on. This dedicated SIP Extension must give Fonolo the ability to dial directly into the queue, bypassing any IVR logic.

You will need to configure:

  • Queue Name: Provide a label for each queue for easy identification within Fonolo.
  • Queue SIP Extension: Provide a SIP Extension that will allow Fonolo to place a call directly into the queue.
  • Fonolo SIP Extension: Fonolo will provide a unique SIP Extension for each queue that you will be offering Call-Backs on.

Once we have received the above queue information, we will provide one unique Fonolo SIP Extension per queue that you will use to transfer calls to for the opt-in process. Fonolo will automatically allocate the extensions used on the Fonolo end, from a 5-digit auto-allocated range assigned to you. If you require Fonolo to use a specific range, please let us know.

Hours of Operation

The Hours of Operation for each queue offering call-backs must be provided as many Fonolo features utilize this field. These hours are used to help Fonolo determine when the queues are open and for operating Call-Back Rescheduling, Call-Back Limiting, and the Responsive Web widget.

You will need to provide:

    • Hours of Operation for each queue to offer call-backs on.
    • Holidays and other times/days when the call center will be closed during the call-back license period.

3. Call Routing/Network Configurations

Fonolo uses several SIP Gateways for inbound and outbound connections to your phone system, which need to be added to your phone system. Also, we will need a public IP address that Fonolo can use to reach your phone system. Lastly, two route patterns will need to be configured (if they do not already exist):

You will need to configure:

  • Provide 1 or more public IP addresses that Fonolo can use to reach your phone system. Load balancing or Fail-over configurations are acceptable. If you are using NAT (Network Address Translation), Fonolo requires 1-to-1 NAT.
  • and are used for call transfers from your system, to Fonolo. You can load balance requests between these two SIP gateways.
  •,,, and are used for calls from the Fonolo system, to your system; for both the call to the queue extension, and for the outbound call to the caller.
  • One routing pattern that matches the inbound extension so Fonolo can connect to the queue directly.
  • One routing pattern to place outbound calls to callers (by default, Fonolo formats outbound numbers as 11 digit numbers- e.g. 1xxxyyyzzzz)

4. Firewall Configurations

For Fonolo to be able to connect to your phone system, firewall rules will need to be applied to permit the required inbound and outbound traffic. Fonolo has 6 SIP Gateways that you will need to be able to connect to:

You will need to configure:

  • Fonolo IP Block will need to be permitted for both inbound and outbound traffic in your firewall.
  • The port UDP/5060 (preferred) or TCP/5060 will need to be permitted (inbound and outbound).
    • Optionally, Fonolo also supports secure SIP using TCP/5061 as an alternative to the above UDP and TCP options. For more details on our requirements, see Secure SIP (SIPS) Requirements.
  • UDP port range matching the media ports on your phone system inbound (to you from Fonolo), and UDP/10000-20000 outbound (from you to Fonolo), will need to be permitted for RTP data.

5. Media

By default, Fonolo uses the following media settings for a SIP connection:

  • g711u (μ-law), with a ptime of 20ms.
  • RFC 2833 / RFC 4733 DTMF

6. IPSec VPN (optional)

Fonolo supports connecting to companies via a direct site-to-site IPsec VPN. For more details, see Connecting via an IPSec VPN.

7. Audio Prompts / Messaging (optional)

There are several audio prompts used by the Fonolo service, some presented to the caller, and some presented to the agent – all of which can be customized by you. This gives you the ability to keep a consistent voice as your callers’ transition on to the Fonolo platform, as well as customize verbiage so you can use preferred terminology.

Visit our Downloads page for a spreadsheet outlining all the files (with suggested messaging), that would be required to support the Fonolo Service.

You will need to provide:

  • For each of the Audio Prompts listed in the spreadsheet, a voice file will need to be generated by your voice talent.
  • Even when using the Fonolo Default Audio Files, you will still be responsible for the initial offer message (ex. “If you’d like to get a call-back rather than waiting on hold, press one now.”)
  • The required format for all Audio Prompt files is .wav, 16bit, 8kHz, mono PCM.

8. Fonolo Portal Setup

Fonolo has an online portal ( where you can manage your Fonolo features and view call stats. To complete the set up of the Fonolo Portal for you, you will need to provide additional information on your company and phone system.

You will need to provide:

  • A list of users who will have access to the Fonolo Portal, as well as their Role within the portal:
  • Stats Only User – Access to view graphs, call logs, and real time stats.
    Standard User– Access to the full portal and can make changes to features and set up new queues
    Admin – Same access as Standard but can manage other users
  • The Hours of Operation for your phone queues, including holiday hours/closures.
  • The Caller ID and Number that you would like your Clients to see when we call them back

9. Agent Training (optional)

In our experience, it is imperative to educate call center reps to give them an idea of what to expect when they receive a Fonolo call, and what the experience is like from a caller’s perspective.

We have provided a simple training document which can be found in our Agents Guide to Voice Call-Backssection, which can be used to enhance your existing training material, or can be provided directly to Agents. It typically does take the Agents a few days to “get the hang of things”, so the sooner they can be notified on when to start expecting Fonolo calls, the better.

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