The term PBX generally applies to all types of telephony systems and stands for Private Branch Exchange which is a private telephone system used within a company providing multiple inbound and outbound lines, call routing, voicemail and call management features. In essence, the PBX handles the routing and switching of calls between your business and the telephone network. A PBX is also known as a PABX which stands for Private Automatic Branch Exchange, but the term PBX is more commonly used.
In the past telephone systems routed calls over the Public Switched Telephone Network (PSTN) which connects telephone lines, fibre cables, microwave transmission links, cellular networks, satellites and undersea cables to switching centres to allow for telephones to communicate with each other. A set of standards and protocols called the Integrated Services Digital Network (ISDN) is used to create a dedicated connection between people for the duration of the voice call.
With the emergence of Voice over Internet Protocol (VoIP), newer PBX technologies use the Internet to carry calls known as IP PBX vs. ISDN or analogue channels such as landlines. In the past traditional PBX technology and its functionality existed predominantly in the hardware, whereas modern systems’ functionality is provided in the software. This makes it easier to add more functions such as teleconferencing, video conferencing, Interactive Voice Response (IVR), integration with the PSTN to support analogue and digital lines, as well as VoIP protocols such as SIP.
SIP stands for Session Initiation Protocol which is a protocol used with VoIP communications – from Internet telephone calls to multimedia conferences. SIP provides the signaling when creating, modifying and terminating sessions between one or more parties. SIP allows companies to take advantage of telephone services and unified communications applications which provide voice, video and other streaming media such as desktop sharing, web conferencing and whiteboard sharing.
Functions of a PBX
The primary function of a PBX is to facilitate a professional process from answering a call, distributing it to the correct person or department and having the freedom to move between an organization in such a way that the client doesn’t have to call back to speak to different people.
A PBX is about connecting telephone users, keeping the connections in place until the call is ended or the user hangs up. With a PBX you don’t have to have one line per telephone per desk.
These days a PBX has become a tool to drive productivity by incorporating technology to manage the communication between clients and staff in a collaborative environment by integrating services such as instant messaging, voice and IP telephony, mobility, audio, web and video conferencing, data sharing, call control and speech recognition with non real-time communication services such as voicemail, e-mail, SMS and fax. This is called Unified Communications also known as collaborative communications and Unified Collaborative Communications (UCC).
PBX’s provide many features such as:
- A single telephone number allowing callers to be speak to any person in the company.
- Automatic Call Distribution (ACD) which distributes incoming calls to specific employees or teams.
- Automated Attendant allows callers to be automatically transferred to an extension without the interventon of a receptionist.
- Call announcements play information to callers, such as company information or business hours.
- Automated call answering, with a menu of options from which a user can select to be directed to a specific extension or department.
- Hunting, where incoming calls are sent to a pre-set group of extensions or a pre-set numerical order.
- On hold, placing callers on hold which waiting for the call called to answer.
- Call forwarding when busy or out of the office.
- Call waiting, blocking or do not disturb.
- Recording customised greetings for any extension.
- Conference calling.
- Interactive Voice Response (IVR) allowing callers to use voice or keypad tones.
- Internal transfer between extensions.
Types of PBX systems
There are different ways to deliver voice systems such as on-premises and virtually through cloud-hosted systems. It is worth investigating the various models with your PBX provider who will guide you to the right system for your business at the price level.
There are three main types of PBX systems: traditional/analogue PBX, Hybrid PBX and IP-PBX.
- Traditional PBX’s are located on-premise at your business, using analogue lines and analogue extensions.
- Hybrid PBX’s are also located on-premise at your business, but they have the capabilities of both analogue, digital and VoIP.
- IP-based PBX’s exclusively use the Internet and can be either located on-premise at your business or hosted offsite on virtual servers.
Traditional Vs. Internet Protocol
Traditional PBX’s are analogue systems which use traditional wiring and are usually separate from your computer networking hardware.IP-based systems use the Internet and are integrated into the same networking systems used for sending and receiving e-mail, web browsing, and other online functions. Using an IP-based system allows you to have all your communication needs handled by one provider, simplifying billing and support issues. With IP-PBX your data network is key; it must be able to handle the additional voice traffic and have the capability to prioritise voice over data.
Hybrid telephone systemHybrid telephone models support older technologies as well as IP-based calling including mobile, landline, ISDN and VoIP calls. In the past telephone systems used handsets that connected to PTSN lines, modern systems now support SIP, ISDN analogue and digital. When choosing a telephone system it is important to ensure scalability, allowing your business to customize and grow into technology. If your PBX and handsets allow for analogue, digital and full IP technology, you will have a seamless transition to VoIP. PBX’s such as those offered by NEC are perfect for the small to medium business that need a telephone system that is scalable from analogue to digital to full IP technology.
On-premise Vs. Hosted PBXTraditional PBX’s and hybrid PBX’s are always located on-premise at your business and come with an outsourced SLA depending on the contract chosen with the PBX provider.An IP-PBX can exist as physical hardware or can carry out its functions virtually (hosted), performing the call-routing activities of a traditional PBX but through software.
IP-PBX on-premise The biggest difference when selecting an IP-PBX on-premise is the capital outlay required – the investment in hardware and server room, as well as depreciation, insurance on the hardware and resource costs to maintain hardware and software itself. On-premise IP-PBX also provides you with the ability to integrate with other software systems your company is running and is ideal for bigger companies who already have the resources, infrastructure and bandwidth to host their own phone system, unified communications platform and VoIP.
IP-PBX hosted With a hosted model, there is no investment in the infrastructure or maintenance costs as you pay an all-inclusive monthly price with a PBX service provider, who owns the responsibility of the entire telephone system.With a Hosted IP-PBX, your Internet connectivity becomes the single point of failure or success. You need to ensure that you have the available bandwidth, speed and consistency required to ensure connectivity to the hosted system. That is why it is wise to have one provider responsible for your Internet and your IP-PBX telephone system.
VoIP systemsWith VoIP the system routes calls over the Internet instead of the PSTN. It breaks down voice data into packets and sends them to the recipient across the most efficient Internet route.
There are some technical reasons why a business’s experience of VoiP is either good or bad. Firstly, data is sent in packets and reassembled on the other side, however with voice the packets have to be sent in the same order as they were sent. SIP allows for voice to be sent in order, as well as sent and received in realtime. In addition, it has to allow for two-way communication, not just one way.
Secondly, latency affects the quality of voice – latency is the term to describe the time it takes a data packet to travel to a local server and back again. This duration of time is known as latency and is recorded in milliseconds (ms). A single voice line travelling at 40 kbps must have a latency threshold of 50 ms. When sending voice through a wireless frequency or copper, it is much slower than fibre and therefore the latency is high which disturbs the voice call, often resulting in time lags and voice distortion.
Thirdly, Quality of Service (QoS) is required where voice either takes priority over data or voice is carried via separate connections.
Finally, the voice gateway either inside a PBX or as a separate gateway, converts the voice calls in real-time between the PSTN and an IP network. This means it decompresses the original voice packets into digital, then converts them into analogue so it can travel on the PSTN, and then back to digital again.
When choosing a provider for VoIP you need to ensure that high quality hardware is used with assurances for Quality of Service (QoS).
With a provider like Zinia their voice servers are on a closed private connection and do not go through the Internet, this means less hops are required to get to the voice server and back. In networking a hop is the number of intermediate devices data must travel between the source and destination. Data packets pass through bridges, routers and gateways and when it is passed to the next network device, a hop occurs. Because Zinia is using Layer 2 protocol not the Internet which is Layer 3, it provides a more direct route to the voice servers and back, which provides quicker latency, better problem resolution and stronger security.
Unified Communication Systems (UCC) UCC systems can be delivered in the cloud, on-site or Hybrid cloud.
- Cloud systems are located in the public cloud / UCaaS / Cloud-based UC / Hosted VoIP.
- On-site systems are on located on-premise either as a single-site, multi-site or virtualized UCC.
- Hybrid Cloud depends on who you talk to and can have many definitions including a combination of on-site and cloud-based UCC systems; a combination of private cloud and public cloud UCC systems and a combination of on-site core voice control system with applications in the cloud.
Virtual phone systems
Virtual phone systems are not fully-fledged telephone systems, they provide a professional ‘face’ to the business by connecting the main business number to remote employees either on their home landline or mobile. This means employees can take advantage of features they do not have on their phone or mobile, including a virtual receptionist, voicemail, call forwarding, call screening and online faxing. However, calls are still charged via your mobile provider or home phone provider, as well as the virtual system fees.
Small to medium sized companies
There are on-site PBX systems which provide the same high-end functions of an enterprise system at affordable pricing for the SME such as Zinia’s Hybrid NEC offering.
Hosted PBX and VoIP technology also provide small to medium sized companies with a cost-effective way to access the benefits of advanced telephone systems which were only accessible to large companies in the past. SME solutions like those provided by Zinia’s hosted service, deliver a PBX telephone system at an affordable monthly fee. This means no upfront costs on the PBX and no service, maintenance or call out fees. It also means your business can scale up or down, depending on your needs.
Choosing the right PBX
Selecting the right PBX solution can be challenging and confusing. How do you decide whether Hybrid, Full IP or Hosted is right for your business requirements? We have compiled a simple scenario guideline for each solution below:Hybrid PBXHybrid is always best for the simpler more price sensitive business. These businesses will get the full functionality of IP without having to spend heavily on user devices. Companies can mix and match based on the business requirements. For example, simplest users can get phones with basic functionality; a few first line managers get digital phones with a little more functionality or if you have a small helpdesk; and you may need a few IP phones for remote sites. A Hybrid system allows your business the flexibility and capability to change and grow into full IP as and when you grow.Full IP-PBXFull IP-PBX is for the business that has an existing network with cabling in place to handle voice. You may need to upgrade from older telephone cabling, move to a new location or have created a new network, whatever the reason your business can add full IP without duplicating on cabling costs.
Full IP-PBX is also for the business who need to implement UCC technology to improve productivity and growth in a collaborative environment by integrating services such as instant messaging, voice and IP telephony, mobility, audio, web and video conferencing, data sharing, call control and speech recognition with non real-time communication services such as voicemail, e-mail, SMS and fax.Hosted PBX Hosted PBX makes sense for the business with very good, stable connectivity and that doesn’t want to outlay the capital expenditure required to get their PBX infrastructure up and running, nor incur any related costs. Hosted PBX provides a simple priced and budgeting model with no additional expenses.Hosted PBX is also ideal for companies with a decentralized setup of lots of smaller sites (offices, branches, individuals). By having one hosted system all that is required is to add phones at the additional sites; there is no need to setup VPN tunnels with routers to connect sites to head office.In addition, Hosted PBX also offers the capability to get the additional functionality provided by Unified Communications (UCC).
Budget required for PBX Every business is unique with different requirements, therefore standard pricing is not available. Your PBX provider should be able to match your business need with the right product, with the right quality of service at the right price. When it comes to choosing a PBX, budget is a huge consideration but should never trump Quality of Service.PBX hardware and physical phones are costly and do require an upfront investment or monthly payment plan. However, the ROI can be high depending on your communication needs and the PBX selected.Larger companies who need the benefits of integrating voice, mobility, unified messaging, presence, conferencing, collaboration, applications and more, require an enterprise system such as the Mitel Unified Communication offering.
Some PBX’s such as the NEC for small and medium sized businesses are easy to setup, manage and maintain, requiring no specialized resources.Hosted PBX prices vary depending on the service provider and are based on the number of employees and the features your business requires.On-premise VoIP also requires an upfront investment or monthly installment for the hardware and phones, as well as installation fees.While IP PBX telephone systems require an investment in equipment and installation costs, over a period of time you may save up to 50% on your average phone bill.If your business does not have the investment, resources or focus required to manage your telephone system, it is worth selecting a hosted option.
Reliability is key Reliability is a key consideration when choosing a PBX service provider: you need the most reliable system for your business needs. Consider the cost of downtime should your telephone system not be available, what is the plan should you lose service and how quickly will you get the service back up and running?With a full IP and hosted PBX there are no analogue lines, which means if the Internet is down, your telephone system is down. If the risk is too great for your business, you will need to build in redundancy. This means implementing two connectivity lines and routers with automatic failover.In South Africa many companies implement a Hybrid PBX which enables them to have analogue lines as backup, should the Internet go down. In addition, the benefit of Hybrid PBX is that even if the Internet is down, employees are still able to communicate internally.Your service provider should also have high a quality and robust data centre with reliable voice servers.Your PBX provider should have the capability to supply and configure a managed device, such as a router or firewall, that will give priority to voice over data, should the load on your bandwidth become too great. Internally, managed switches should also ensure Quality of Service (QoS), giving voice a priority.
Availability of in-house, skilled IT resources
If you do not have your own internal resources, then you will need 24/7 support. Make sure you know how and who to contact for support and the time to respond written in your Service Level Agreement (SLA). In addition, you need to ensure that your provider has the skills and ability to do proper installations and configurations of the PBX.
Most PBX’s come with some mobile functionality but you need to evaluate this against your current and future requirements. If you have a high amount of employees who use their smartphones or other mobile devices, you may need more capabilities than forwarding calls to their devices. With hosted PBX systems multiple offices can connect over the same system and not incur inter-office call charges.
It is best to choose a telecoms provider who has the experience to guide you to implement the right system for your business based on your needs and budget.