Telephone Systems: A Buyer’s Guide to PABX and IPBX

This phone buyers guide has been created to help 1st Communications’ customers choose the ideal business telephone system for their respective needs. Here we discuss considerations that should be made by UK businesses ahead of choosing a PABX or IPBX telephone system, and explain the capabilities, limitations and benefits offered by the different telecommunication systems available. We have also produced a glossary, to help anyone confused by industry jargon or the definition of certain features. CONTENTS:

Considerations for choosing a telephone system

Lead times

Many businesses choose to upgrade their telephone system as part of a move to new premises. Moving office can be very stressful, and making decisions regarding your telecommunications set-up as far in advance of your move as possible is highly recommended. New basic and ISDN (digital) lines, and Broadband packages, can take up to a month to be installed once ordered, so they are a crucial influence on relocation timescales. Businesses seeking a new telephone system, but not as part of a move, should still be aware of lead times, as new lines may be required as part of a system upgrade.


Do you know the type of cabling your current or future premises has installed? It may be sufficient for your new system’s needs, but you will need to have the current cabling analysed to be sure. You need to understand the current specifications before ordering any system to ensure compatibility, and to determine any additional cabling requirements.


You’ll also want to consider the expansion goals of your business when choosing a telephone system. Uninstalling a perfectly good system simply because you have reached its capacity is obviously not ideal! Some key systems can be expanded should VoIP lines be used, but for large businesses (40+ employees), easily expandable and advanced feature-compatible PBX systems are the ideal choice. Businesses operating internationally, meanwhile, should seriously consider a VoIP-based system.


While many telephones, accessories and add-on options are compatible with a multitude of telephone systems, it is always important to check whether your current equipment (if relevant) will work as part of your planned upgrade. It may be the case that certain peripherals will need replacing – if you’re unsure, please don’t hesitate to contact 1st Communications for expert advice.


This is obviously a key concern for any business, and 1st Communications has systems to suit any budget. In addition to brand new telephone systems and the related equipment, we also provide many refurbished options – all of which come with one year’s warranty. And if you’re looking to upgrade your current system, we’ll discount your order in exchange for your old equipment, which we’ll then recycle.

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Confused by any terminology used above? Skip to our glossary

What is a key telephone system?

Key telephone systems are multiline systems suitable for up to 50 users. While Private Branch Exchange (PBX) phone systems see outgoing lines selected automatically, key systems require users to manually choose a line to dial out from. Key telephone systems comprise a central control device known as a KSU, or key system unit. It is this unit that provides convenient features missing from standard telephones, including call forwarding to in-office extensions. This unit can also prevent users from trying to use lines that are in use by fellow employees. As time continues, the difference between key and PBX systems has become harder to distinguish. Many modern key systems comprise features which were once only available on PBX systems, and functionality can often be changed depending on the software that is implemented. Alternative KSU-less phones are also available. These offer similar functionality for a lower price, in the absence some of the more specialised (i.e. costly) technology found in pure KSU hardware. The fact the majority of KSU-less handsets can meet the telephony needs of 10 users only however, often makes them a non-viable option for growing businesses. Is a key telephone system ideal for my business? To determine whether or not a key system is suitable, you should consider the following pros and cons: Advantages of key systems
  • Suitable for businesses with up to 50 employees
  • Convenience of proprietary handsets, designed to work specifically with the installed key system
  • One-size-fits-all functionality
  • Can be easily customised with software upgrades
  • Reliable
  • Minimal maintenance required
Advantages of key systems
  • Unsuitable for businesses with more than 50 employees
  • Advanced functionality (such as auto attendant and ring groups) can often be lacking when compared to PBX systems (despite the before-mentioned fact that the gap between the two options is increasingly blurred)

Think a key system suits your business? Call 1st Communications today on 0207 5534 488 to discuss your needs and learn about our fantastic bulk discounts.

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What is a PABX (PBX) telephone system?

A PABX – or Private Automatic Branch Exchange – is a type of private telephone network used internally by businesses. Such systems connect on-premises terminals to each other without the need to rent costly lines for each, while users share a number of outside lines to make external calls. It once was the case that these systems were called PBX systems, because they required the use of a live operator (i.e. they were not automatic). The two acronyms are used often used interchangeably to refer to the modern automatic variants. PABX systems comprise a control box, through which the system’s functionality can be controlled. It is often the case that these PABX boxes must be plugged into an external PC or laptop (with particular software installed) to be administrated. A business may require an external technician to complete installation and maintenance. It is worth noting that an increasing number of PABX systems comprise data lines, to allow the benefits of VoIP (Voice Over Internet Protocol) technology to be utilised (read more). Virtual PBXs are also available over the Public Switched Telephone Network (PSTN). These are systems hosted by large telecoms companies, providing PBX functionality to businesses as a premium service. Is a PABX system ideal for my business? To determine whether or not a PABX system is suitable, you should consider the following pros and cons: Advantages of PABX systems
  • Negates the need to have direct lines for each individual terminal, keeping line rental overheads low
  • Automatically routes incoming calls to specific extensions
  • Interconnected on-premises terminals can call each other free of charge, encouraging good communication and efficient business operations
  • Calls can be logged automatically, aiding understanding of where time and/or money can be saved within an organisation
  • Feature rich
Disadvantages of PABX systems
  • Can be an expensive (but worthwhile) business investment
  • The services of an external technician may be required to keep a PABX system operating smoothly

Interested in a PABX telecoms system for your business? Call 1st Communications today on 0207 5534 488 to discuss your needs and receive a no obligation quote.

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What is an IPBX (IP BPX) telephone system?

An IPBX (Internet Private Branch Exchange) – also referred to as an IP BPX – is a telecommunications system that allows calls to be conducted over internet protocol data networks, with conversations sent as data packets. IPBXs are often considered to be the best choice for mid to large businesses, since they are feature-rich (auto attendant, voicemail, ring groups etc.), software-based (allowing easy installation and greater customisation) and offer problem-free, and cost-effective, scalability. With a conventional PBX, voice and data communications require individual networks. The fact an IPBX employs converged data and voice networks is often cited as their greatest benefit – web browsing, VoIP, and standard phone conversations can all be conducted through single lines. This not only reduces maintenance and long-term operation overheads for businesses, but also provides the unrivalled flexibility expanding operations require. Like a traditional PBX, an IPBX is owned by the enterprise and is not dependent on proprietary hardware or software. Virtual IPBXs are also available over the Public Switched Telephone Network (PSTN). These systems see IPBX functionality hosted by large telecoms companies, who charge businesses to make use of the service. Is an IPBX system ideal for my business? To determine whether or not an IPBX system is suitable, you should consider the following pros and cons: Advantages of IPBX systems
  • Simpler to install and configure than proprietary phone systems
  • IPBX systems are easier to manage, thanks to web/GUI-based configuration interface
  • Hardware phones can be plugged in to standard PC network ports, eliminating the need for excessive phone wires
  • Growing businesses can scale their IPBX system easily and economically
  • Routing long distance and international calls through the internet can save businesses a great deal money
  • IPBX systems are software-based, meaning it is easier for developers to add and improve upon their features compared to alternative systems
  • Employee hot desking and roaming is easiest with IPBX systems
  • Allows integration of phone functions with business applications (for example, a customer’s file could appear on screen when they call)
Disadvantages of IPBX systems
  • Can be an expensive (but worthwhile) business investment
  • IPBX systems are potentially less secure than alternatives due to internet connectivity. However, this issue can be resolved with the implementation of strong passwords and firewalls, and by restricting the number of features available outside of a business’s LAN (Local Area Network)

Call 1st Communications today on 0207 5534 488 to get expert IPBX advice and receive a free no-obligation quote.

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What is a hybrid telephone system?

Essentially, hybrid systems can be considered a cross between basic key systems and the more complicated private automatic branch exchanges (PABXs) often installed at large organisations. Like key systems, hybrid systems are low cost and easy to manage but they offer more features, plus greater flexibility and scalability. Hybrid systems comprise signal management codecs, which allow them to route both analogue and digital signals to appropriate terminals. Calls over traditional local telephone lines can be completed but hybrid systems also provide the option of routing certain calls over the internet to benefit from features available in VoIP systems. One of the most traditional applications of hybrid systems has been to connect a business’s main analogue line to its more complicated internal telephone system, essentially operating its own private branch exchange (PBX). The implementation of a hybrid system in this instance negates the need for dedicated analogue and/or digital telephone lines for each internal business site. Is a key telephone system ideal for my business? To determine whether or not a key system is suitable, you should consider the following pros and cons: Advantages of hybrid systems
  • The most modern hybrid systems offer ‘the best of both worlds’, combining key system and digital functionalities
  • Hybrid systems can offer many of the benefits of pure VoIP systems, at a much lower price point
  • Routing long distance and international calls through the internet can save businesses a great deal of money
  • Hybrid systems can increase productivity by allowing the efficient transference of calls to the correct extensions, both inside and outside of the main business premises
Disadvantages of hybrid systems
  • Technicians responsible for the smooth operation of a hybrid system will need to be familiar with key system, PBX and VoIP technologies

Think a hybrid system is the ideal choice for your organisation? Call the 1st Communications experts on 0207 5534 488 today for a no obligation quote.

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