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Asterisk Phone Systems Review

What is Asterisk?

Asterisk is an IP PBX (private branch exchange), operating as a central point of communication in a company. It operates using a business’s internet connection, removing the need for traditional landlines to provide a greater level of flexibility and an increased number of features. Founded by Mark Spencer whilst he was still at university, Asterisk is a free, open-source platform that allows phone systems to be customised to a business’s unique needs. Using Asterisk, an ordinary computer can be used as a communications server, allowing businesses to easily manage a PBX, IVR system, conference bridge, and much more.

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IP PBX (Internet telephony Private Branch Exchange) represents a unified communications system which provides for central switching control for all calls within a business environment. Handling internal traffic between departments and acting as a gateway to external communications, a Public Branch Exchange is a historical term for a system which has experienced significant evolution over the last 100 years and now offers a raft of solutions including call waiting and call divert, voice messaging, mobile provision and conferencing facilities. The Asterisk product is both future proof and protocol and technically agnostic, offering users a number of options for the construction of their PBX services. For those businesses which require total control over the operation of their system, have a set of highly specific demands or are creating a service or product from the bottom up, building their PBX from scratch can provide the best option.

Asterisk PBX

With Asterisk PBX, businesses have access to unified communications, allowing one-on-one phone calls, text messaging, videoconferencing, integrated email, fax, chat, and instant messaging. All of this is funnelled through one scalable system, making changes and updates easy. IP PBX has a variety of benefits to businesses of all sizes, making them a popular choice as organisations choose new systems or update existing telephony.Asterisk PBX brings a variety of features to businesses, including:
  • Customised pricing options - Features can be customised to meet a business’s budget. Instead of paying for features or minutes that it will never use, a business pays only for the features it uses each month.
  • Freephone service and DIDs - Freephone numbers are available for businesses that need to offer customers the ability to call in for free. With Direct Inward Dialling, lines can be grouped to let calls be more easily managed.
  • Fully-controlled phone systems - Businesses hire teams of developers to develop and maintain customised applications. With the Asterisk framework, developers can develop and maintain customised phone functionality, adding and removing features as necessary.
  • Pre-packaged solutions - Even businesses without access to developers can utilise Asterisk. The Asterisk Exchange Marketplace features a list of packaged solutions available to businesses of all sizes.

Benefits of Using Asterisk

Asterisk IP ProductsOpen-source solutions are popular with developers because they allow full customisability without the price. Whether a business chooses a packaged solution or to take advantage of the Asterisk open-source framework, there are several major benefits of the solution.
  • Flexibility - Open-source software gives developers the ability to explore the programming in depth and make any changes necessary to achieve the desired end result.
  • Simplicity - Asterisk removes the complexities associated with telephony to create a simple, completely customisable interface that provides the communications options necessary.
  • Scalability - Because Asterisk is fully customisable, the system grows with an organisation. When a new employee joins the staff, a new phone number can be assigned immediately and menu options on phone directories can also be updated. All of this is done in-house, leaving the business in control of its own system.
  • Stability - Asterisk’s interface delivers the stability and reliability a business needs, with security and updates issued on a regular basis.

VoIP Gateway Solutions

A VoIP (Voice over Internet Protocol) gateway creates a connection between traditional legacy telephony and VoIP by linking PBXs with VoIP technology. A gateway will provide the user with a good way to integrate features into a system in addition to reducing costs. The gateway connection is via analogue or digital trunk ports; calls from PBX to external applications are converted and transmitted over the internet to the VoIP service provider while those from a VoIP source are converted to the appropriate legacy protocol for delivery to the PBX. The implementation of a gateway can prolong the life of legacy hardware by enabling VoIP application through the replacement of traditional trunk lines with SIP (session initiation protocol) trunks or by rerouting by toll bypass; the process of rerouting a subset of traffic to a remote gateway of PBX via VoIP. Asterisk enables the construction of a VoIP gateway by using a computer in combination with one or more telephony interface cards. An alternative option is to use one of the Digium ranges of turnkey gateway solutions built using Asterisk. The end product will deliver a more cost effective and flexible solution than allowed by traditional legacy gateway applications due to the multi-protocol modular architecture of the Asterisk software.

Asterisk Solution for IVR

Interactive Voice Response (IVR) provides the automation of customer service through its ability to allow callers to interact via voice response or touch-tone digits. Benefits include a significant cost reduction when compared with employing staff to perform repetitive boring tasks and the ability to support multi-language delivery, providing the business with global coverage to non-domestic markets and to multilingual clients at home. An efficiently configured IVR system will also provide high quality customer service 24/7 during periods when the office is empty in the evening and at weekends. Asterisk offer a broad platform of IVR functionality providing:
  • Digit Collection
  • Audio Recording and Playback
  • Calendar integration
  • Web accessibility
  • Optional speech synthesis
  • Recognition
Utilising Dialplan language applications or Asterisk Gateway Interface features, the software is suitable for most external systems. With no per-port or per-concurrent-call licence charge and run on low cost PSTN (public switch telephone network) interface and commodity hardware to ensure that the cost of deployment is kept as low as possible, the open nature protocol also enables the user to alter the base functionality via the Asterisk source code. With the opportunity to build or buy, users can opt to construct their own IVR solution through Linux telephony and script development or select a prepackaged solution such as AsteriskExchange or Digium Switchvox.

How Businesses Use Asterisk

Ounce of Protection LogoBusinesses of all sizes have successfully switched to Asterisk for their communications needs, including nonprofits. Chicago-based Ounce of Prevention used Asterisk’s Switchvox unified communications system to reduce its monthly telecommunications costs by the equivalent of £6,500. Large businesses and organisations have successfully deployed Asterisk as well. In 2011, the Belgian province of Luxembourg migrated from Cisco to Asterisk due to its lower cost and ability to keep its existing infrastructure. The seamless migration allowed the province to save money and migrate toward Open Standards (SIP).


Asterisk offers two pricing plans. The first is a metered rate plan that charges companies based on a set rate per minute of usage. This option may be best for small businesses and companies with fluctuating usage from week to week. A channelised rate plan provides a set, predictable monthly bill that allows unlimited inbound and outbound calls. Asterisk is a flexible, reliable telecommunications solution for businesses of all sizes. The affordable cost and scalability makes it a popular choice in an era when technology needs are constantly evolving.