SIP w/ Appliance 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 hybrid SIP connection that includes placing on-premise appliances within your network for an additional layer of security and for PII and PCI compliancy.

This guide will outline the necessary steps, and information that we require, to set up a hybrid SIP connection between your phone system and the Fonolo Cloud – you can return the specific information required for your Fonolo deployment using the Hybrid 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 hybrid 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. Physical Appliance Specifications

The Physical Fonolo Appliances are 1U rack-mount Dell servers, running a mix of open-source and custom-built software, that are installed on your premise and remotely operated, managed, and monitored by Fonolo, as part of the Fonolo call-back license.

The Physical Fonolo Appliances include:

  • Dual 1GB network ports that can be configured as a single interface, as LACP, or in Master/Slave mode.
  • Dual redundant power supplies (110-240v, C13)
  • Dual mirrored hard drives.
  • Four post or two-post (relay rack style) rack-mount rails.

4. Network Configurations

Before Fonolo can ship you your Physical Appliances, you must provide Fonolo with network configuration settings so they can be preconfigured.

You will need to provide:

  • Determine connection mode: single interface, or dual interface (as LACP or in Master/Slave mode)
  • IP address / subnet for each network interface
  • Gateway IP address
  • 1 unique, externally routable IP address per Appliance
  • The Private (and if NAT, Public) IP address of the phone system

In the case where your network has NAT (Network Address Translation) set up, Fonolo requires 1-to-1 NAT. Port-Based NAT will not work with the Fonolo Call-Back service.

If the Appliances will be behind a NAT gateway, Fonolo will need both the public IP address (for remote connections), as well as the private IP address information to configure on the network interfaces.

You will need to provide:

  • The public IP addresses of your NAT gateway that Fonolo can use to connect to your network.

If the Appliances are to be used behind a NAT gateway, NAT timeout rules will need to be adjusted to make sure that connections aren’t dropped mid-call, as the SIPS connections between the Fonolo Cloud and the Appliances often have long periods with no data transferred. We would suggest a 4-6 hour timeout.

Fonolo’s RTP voice traffic utilises QoS with TOS=EF, CoS=5 by default. Please integrate this configuration to ensure the best possible voice quality across your network.

5. Call Routing Configuration

The Appliances must be added to your phone system (as SIP gateways, entities, trunks, etc. depending on system) using the addressing provided above.

Two route patterns will also need to be configured (if they do not already exist):

  • 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)

6. Firewall Configurations

Since the exact location that the appliances will be placed will vary from company to company, a different version of the following firewall rules may be required.

The Fonolo Appliances will need to be able to speak to your phone system, to the Fonolo Cloud, and to each other as well.

For the Fonolo Cloud to be able to connect to the Fonolo Appliances, external firewall rules will need to be applied to permit the required inbound and outbound traffic.

You will need to configure:

  • Fonolo IP Block will need to be permitted for both inbound and outbound traffic in the firewalls in front of the Fonolo Appliances.
  • The ports TCP/5061 (SIPS), TCP/22 (SSH), TCP/443 (HTTPS), UDP/123 (NTP) and TCP&UDP/53 (DNS) will need to be permitted (inbound and outbound) in the firewalls in front of the Fonolo Appliances
  • If there is an additional firewall between the Fonolo Appliances and your phone system, ports UDP/5060 (SIP) and UDP/10,000-20,000 (RTP traffic) will need to be opened.
  • Many phone systems use a feature called “Direct Media” or “Re-invite“, and in this case, the Fonolo Appliances will also need to speak to other media devices, such as Media Gateways and Agent Handsets, so these IPs will also need to be permitted (IB/OB) within the firewall.
  • The Fonolo Appliances also need to continuously speak to each other, and they do this via TCP/443 (HTTPS), so this will also need to be permitted.
  • For Appliance pair redundancy, and audio failover, ports UDP/10,000-20,000 (RTP traffic) should also be allowed between the Appliances.

All network ports referenced above (TCP/5061, TCP/22, TCP/443, UDP/123, TCP&UDP/53) are required for the Fonolo Appliance service to work.

Fonolo frequently scales resources up or down depending on workload and may vary the production IP addressing within the named subnet at any time – do not attempt to identify individual hosts for protocol exceptions, as this may prevent the solution from working as intended.

7. 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.

8. Media

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

You will need to configure:

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

9. 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.

10. 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

11. 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-Backs section, 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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