PBX phone system installation

Find out how to get up and running in a jiffy with either a hosted or on-premise PBX system

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This page will cover the process of PBX office phone system installation, whether that’s through a hosted or cloud-based PBX system, as well as an on-premise PBX system relying on your business phone line setup.

You may need installation services for a number of reasons:

  • Installing a new system – if you’re updating a traditional analogue phone system
  • Deinstallation/ reinstallation – if you are moving offices. Professionally trained engineers can help with this for minimum disruption

Whatever the reason, for complicated or potentially dangerous electrical installations, remember to seek professional help.

This article will cover:

Hosted PBX installation

As the server is located with your provider for hosted PBX, you just need the phones and a central computer at your location.

Your office connects to the provider’s SIP trunk through an approved data connection, which then connects to the public switched telephone network (PSTN).

This sort of cloud-based PBX system also allows remote users to connect via any device  using existing internet connections.

Handsets can be pre-configured by the supplier, then set up at your location on a ‘plug-and-play’ basis.

If you need to configure your own phones, follow these simple steps:

  1. Plug the phone in and connect it to your network
  2. Find the IP address of the phone in the phone menu
  3. Type that IP address into a web browser to find the telephone configuration menu
  4. Nominate an extension number to configure into the phone
  5. Fill in the requested details
  6. The phone and extension number will now be registered with the provider


What about extensions?

Additional handsets can be requested from the supplier and sent out ready to be plugged in for immediate use. Follow the steps above to configure new extensions.

On-premise PBX telephone system installation

Setting up an on-premise PBX system is a little more complicated. In most cases, you will need the help of a trained professional – both for the initial installation and ongoing maintenance.

If you are buying a new PBX system, the installation (and a technician) will usually be included in the cost.

There are many components to a full small businesses PBX deployment. You will need the following equipment:

On-premise PBX equipment

Broadband router

In order for your IP (internet protocol) phones to work, they need to be connected to an internet network.

This will be done through a broadband router set up in your office. You can read a comprehensive guide to choosing business broadband here.


Provided you have the rest of your PBX infrastructure set up, most IP-PBX phones should be ‘plug-and-play’.

This basically involves following a few simple steps:

  1. Plug the telephone cord into the ‘telephone line’ input on your PBX console
  2. Connect the other end into a wall jack (allowing it to make and receive phone calls)
  3. Insert the PBX plug into the console, and the other end into the wall outlet

A central server

The server manages the calls by switching them from one line to another depending on what number is being dialled.

This requires physical lines to be run throughout the building. Calls are then routed through a traditional phone company via SIP Trunking.

SIP trunk

SIP stands for Session Initiation Protocol (SIP).

A SIP trunk is a virtual method of connecting phone calls to the Public Switched Telephone Network (PSTN). This allows phone calls to be sent and received digitally.

The SIP trunk is stored in the same place as your server.

Digital telephony cards

These are hardware components of a telephone systems that plug directly into the server of your PBX system.

They are used to expand your system to allow for a higher number of high quality, simultaneous calls.

For example: a 4-port voice and data card would allow for 120 simultaneous calls.

Step-by-step guide to setting up your on-premise system

Once you have all the equipment, you’re ready to set up your on-premise PBX system.

Here’s how:

  1. Choose an operating system

This will depend on what operating systems are compatible with your PBX – usually Windows or Linux. To ensure everything performs at full capacity, you should ensure that:

  • Your system has least one (1) CPU core and one (1) Gigabyte of RAM
  • You are using the latest software (install all updates)
  • You switch off scanning on any Antivirus software
  1. Run your PBX

Once you’ve installed the PBX , it needs to be configured for your network. Most systems will take you through a step-by-step process to enter the relevant information.

  1. Configure your firewall and router

You’ll then need to make changes to your firewall configuration to ensure your PBX system successfully communicates with your SIP trunk and remote phones.

This will require you to configure certain ports dependent on your system. To maximise effectiveness, make sure you choose a device that does not use a SIP helper.

  1. Import users/ extensions and deploy apps

You can import users/ extensions by importing a spreadsheet/ CSV file directly into the PBX system. The users will then be able to make and receive calls and be added to the company phonebook.

  1. Configure your SIP trunk

This will allow you to make outbound calls. To do this, you need to:

    • Have adequate bandwidth (each call consumes approx. 30-120 kb per second)
    • Have a firewall that allows you to switch off a SIP helper
    • Create an account with a supported VoIP provider
    • Add the VoIP account to your PBX system

  • Create an outbound rule to dictate that the outgoing calls will be routed through the SIP trunk

Scaling your PBX system

One of the benefits of a PBX system is that they’re quite easy to scale. All you need to do is add additional lines or extensions.

In the case of hosted PBX, this may simply require you to contact your provider and pay a small fee.

If you have an on-premise system, a technician may need to come into your offices and add additional lines – unless you have the IT support to do it yourself.

Next steps

Once your PBX system is set up, you’re ready to hit the ground running and start making calls.

That’s not to say you won’t encounter maintenance issues or require repairs. But, with a good supplier, this should be rare and cause minimal disruption to your business.

If your business starts to scale, it shouldn’t be too difficult to scale your PBX system with it.  You just need to add additional lines and users.

If you haven’t done so already, make sure you check out our pages on what is PBX? and the costs of PBX.

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Written by:
Henry Williams headshot
Henry has been writing for Startups.co.uk since 2015, covering everything from business finance and web builders to tax and red tape. He’s also acted as project lead on many of our industry-renowned annual indexes, including Startups 100 and Business Ideas, and created a number of the site’s popular how to guides.
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