How to set up a telephone system for your office from scratch

Why office telephony is more than just a phone number

The telephone remains the primary channel of contact for most businesses. According to statistics, over 60% of customers in the service and retail sectors choose to call when they want a quick response or to place an order. But the difference between «just a phone» and a «telephony system» is enormous.

When telephony is disorganised (relying on employees’ personal numbers), a business faces several real problems. Firstly, no one keeps track of missed calls: a customer has gone to a competitor, and you don’t even know about it. Secondly, the quality of service depends on the individual rather than the system. Thirdly, when an employee leaves, they take «their» contact database and «their» number with them. Finally, there is no analytics: how many calls there are, how many are missed, what the average call duration is — none of this is known.

A properly organised corporate telephone system tackles all these issues at once. It provides the company with a single number, a clear call-handling process, monitoring and statistics.

What makes up modern office telephony

To avoid getting confused by the terminology, think of office telephony as a construction set made up of several components. Each plays its own role, and only together do they produce the desired result.

● Telephone number

This is the «face» of your communications — the number the customer dials. The number can be a local number (057, 044), a national number (089) or a freephone number (0800). Important: a single number can handle several calls simultaneously — this is known as multi-channel capability.

A special case arises when it is important for a business to retain a mobile number as its primary contact: customers are already used to it, and it appears on the website and in advertising. In such cases, a GSM gateway is used — a device that integrates a mobile SIM card into the overall telephone system. Thanks to this, calls to the mobile number are routed through the PBX in the same way as calls to a landline: they are distributed among staff, recorded and forwarded. The mobile number remains, but is no longer tied to a specific phone in the manager’s pocket. However, this solution has many limitations and nuances that can affect operational stability.

● SIP channel or SIP trunk

If a telephone number is an address, then a SIP channel is the route along which a call travels. IP telephony is a technology for transmitting voice over the Internet using the SIP (Session Initiation Protocol). It is this technology that enables calls to be made and received via the network, rather than via a traditional telephone line. Compared to traditional telephone services, VoIP does not require physical lines, is easily scalable and is significantly cheaper to maintain — particularly for companies with high call volumes or distributed teams.

● PBX – Private Branch Exchange (cloud-based or on-premises)

A PBX is the «control centre» of your telephone system. It determines: where to forward a call, what to tell the customer via the voice menu, who to transfer a call to in the queue, and what to do outside of working hours. Without a PBX, a number simply rings — and that’s it. With a PBX, it becomes a tool.

● End-user devices

These are the tools your staff use: an IP phone on their desk, a softphone on their computer, a mobile app or a headset. The choice depends on the task: a call centre needs a comfortable headset, whilst a sales manager needs a smartphone app to work from anywhere.

● Internet connection and network

The foundation of the entire system. Call quality depends directly on the stability of the Internet connection. Even the most expensive PBX won’t save the day if the connection is unstable or if voice traffic isn’t prioritised on the office’s local network.

● Routing logic and additional services

These are the «rules of the game»: who answers first, and what happens if the line is busy. Plus: call recording, statistics, and integration with a CRM system.

What are the different models for setting up a telephone system?

There are three main models for setting up a business telephone system, and the choice between them depends on the size of the company, its budget and the level of control required.

1. Cloud telephony. There are two possible approaches here.

The first is SaaS telephony: you use a ready-made subscription service, where the functionality, updates and support are provided by the solution developer. This is the quickest and easiest option to get started.

The second is your own virtual PBX: you deploy the telephone system yourself based on Asterisk, FreePBX or similar solutions on your own or rented servers (VPS/cloud). This gives you full control over settings and data, but requires technical expertise and resources for support. Read our article for a detailed comparison of both approaches.

2. Hardware-based IP PBX systems. These are ready-made hardware solutions from specialist manufacturers such as Cisco, Grandstream, Yealink, Fanvil and others. Such devices are available in various configurations and differ in terms of functionality, the number of supported lines and scalability — ranging from compact solutions for small offices to full-scale enterprise systems.

The equipment is housed locally in your office and provides full control over the infrastructure, but comes with certain requirements: you need physical space for installation, regular maintenance, and your own IT specialist or contractor responsible for system support. This model is justified where full control over the infrastructure is critical or where there are specific security requirements.

3. The hybrid option. Part of the infrastructure is deployed in the cloud, and part locally. This format is suitable for companies that already have certain equipment or have specific requirements for individual functions.

Where to start: key questions before launch

Before choosing a solution, it’s worth answering a few questions. They may seem obvious, but it’s precisely ignoring them that leads to having to redo everything a year down the line:

• How many staff members will be using the phone system?/li>
• How many simultaneous calls might be received?
• Do you need a single number for the whole company or separate numbers for departments?
• Do employees work only in the office or also remotely?
• Do you need call recording?
• Is there a CRM system that needs to be integrated?
• What happens to calls outside working hours?
• Do you have a plan for scaling up?

Which number and connection type to choose

Once the basic issues have been resolved and the optimal telephone system model has been selected, it is time to decide on the types of numbers:

• A local area code (e.g. 057 for Kharkiv, 044 for Kyiv) — a classic choice that inspires confidence in customers.
• An 0800 number is free for the caller, which works well for customer support and increases the number of enquiries.
• An 089 number is a nationwide virtual telephone number designed for making calls over the Internet.

When choosing a number provider, ensure they support multi-channel capability and the SIP format. Multi-channel capability allows you to receive multiple calls simultaneously on a single number — without this, customers in the queue will simply hear «busy». The SIP format means that the number is virtual, i.e. not tied to a physical line: it can be used from any device and easily scaled without additional equipment.

But the number alone isn’t enough. For businesses, it’s not just about «where calls go», but also what happens to the call afterwards. Even the best number won’t save the day if there’s no system in place to handle it. Key features that should be considered from the outset: how many calls can be handled simultaneously, how to distribute them among staff or departments, what happens if everyone is busy — a queue or call forwarding — and how calls are handled outside working hours. It is precisely this that turns a number into a tool, rather than just a contact on a website.

For a small team of up to 5-7 people, where everyone handles similar tasks, a single multi-channel number with simple routing is quite sufficient. But if the company has separate departments (sales, support, accounts), it’s worth planning a structure with multiple channels from the outset. For example, one number for customers, a separate internal number for the team, and an 0800 number for the helpline. This doesn’t complicate the system — on the contrary, every call goes straight to the right person, rather than being passed between departments.

What equipment might be needed for telephone communications in the office?

Not every office needs a traditional telephone on every desk. When choosing equipment, focus on the specific workflow of each employee rather than on habit. Here are some practical options:

• IP phone — ideal for receptionists, secretaries and call centres. It looks familiar and doesn’t require a computer.
• Softphone (software on a PC or laptop) — ideal for managers who spend all day at a computer anyway.
• Mobile app — for staff on the move or working remotely. Make calls via the office number from a smartphone.
• Headset — a must-have for call centres or active sales: hands-free, better sound quality.
• VoIP gateway — only needed if you have old analogue equipment that needs to be integrated into the new system.

What sort of Internet connection and network are needed for reliable telephony?

This is one of the most important — and often underestimated — aspects. It is also the first thing to consider when setting up a telephone system in the office. You can buy an excellent PBX and high-quality telephones, but if the Internet connection is unstable, the voice will «break up», calls will drop, and customers will get annoyed.

What to look out for:

• Stability, not just speed. A 10 Mbps connection with a stable signal is better than a 100 Mbps connection with constant micro-disconnections. Each voice call requires a speed of only 80-100 kbps, but it requires a consistent, uninterrupted flow.
• Latency (ping) and packet loss. Ideally, ping should be up to 50 ms with zero packet loss. Otherwise, an «echo» effect occurs or words are «swallowed».
• QoS — prioritisation of voice traffic. If someone in the office is downloading a large file and QoS is not configured, call quality will suffer. A properly configured network «prioritises» voice traffic.
• Backup connection. If the main Internet connection goes down, the phone line goes silent too. A backup connection (even a mobile 4G router) saves your reputation at a critical moment.
• Availability of white IP addresses. This is an advantage, as it simplifies configuration and improves operational stability.

Maxnet provides business Internet with guaranteed line quality, including a backup option. Combining digital telephony and Internet services from a single provider allows you to configure QoS without the need for additional coordination between different contractors.

Which features does a business really need?

Modern telephony solutions support a wide range of features. But which ones are actually used in practice, and which ones really make a difference to the business? Let’s take a closer look.

• Internal extensions. Each employee is assigned a short internal extension (101, 102, etc.). Transferring a call to a colleague takes just one button press. The customer doesn’t have to wait while the manager «checks and calls back».
• Voice menu (IVR). «Press 1 for sales, 2 for support» — sound familiar? That’s IVR. It allows calls to be routed without a receptionist and directs the customer straight to the right specialist. Even a simple two-option IVR significantly reduces the number of instances where a customer ‘ends up in the wrong department’.
• Queues and call distribution. If all managers are busy, the customer waits in a queue with music playing, rather than hearing «busy» and hanging up. The system automatically distributes calls among available staff.
• Call recording. This is critical for sales, support and any company where the spoken word has legal significance. It enables you to train your team, resolve disputes and monitor service quality.
• Statistics and analytics. How many calls were received? How many were missed? What is their average duration? Which managers are the busiest? Without this data, managing the sales department is almost like flying blind.
• Out-of-hours scenarios. The office closes at 6 pm, but customers still call in the evening. The system can automatically forward calls to the on-duty staff member or provide information about opening hours. The customer receives a response, not silence.
• Integration with CRM. When a customer calls, the manager immediately sees their profile in the CRM: who they are, what they’ve ordered, and what queries they’ve had. The call is automatically logged in the history. This isn’t a luxury — it’s a basic standard for any serious sales department.
• Agent dashboard. An essential feature for supervisors, call centres, support teams, etc.

How to set up a telephone system from scratch: a step-by-step guide

Setting up a telephone system from scratch only seems complicated until you break it down into specific steps. In fact, the entire process — from the initial idea to the first call — can be completed in a matter of days if you follow the right sequence.

1. Draw up a technical specification. First and foremost, set out on paper (or in a document): how many people, how many calls, what features are needed, whether there is a CRM system, and what the budget is. This will take an hour, but will save weeks of rework.
2. Choose a provider and a PBX model. Before choosing a provider, decide on the model. Cloud telephony (SaaS or your own PBX on Asterisk/FreePBX) requires no office equipment and is the quickest to set up. A hardware IP PBX is hosted on-premises and offers full control, but requires maintenance. A hybrid option combines both approaches. For most offices, a business-grade cloud PBX from a reliable provider will suffice. It is important that the provider supplies both Internet and Telephony: this simplifies support and avoids situations where one party blames the other for problems.
3. Prepare the network. Check the quality of the Internet connection, configure QoS on the router, and ensure that the office Wi-Fi does not «swallow» voice packets. This is one of the key technical aspects when installing a telephone system in the office. Therefore, if in doubt, it is best to consult a specialist.
4. Purchase and configure the equipment. Select devices for specific workstations, register them in the PBX system, and check call quality.
5. Set up the routing logic. Configuring the virtual PBX includes voice menus, queues, call distribution among staff, and out-of-hours scenarios. Once configured, be sure to test it: make a call yourself and go through the entire customer journey.
6. Integration with CRM and launch. Connect the telephony to the CRM system, train the team and launch the system. The first week involves monitoring and minor adjustments.

Examples of solutions for different types of offices

The choice of a specific telephony configuration is largely determined by the size of the team, the nature of the work, and typical call-handling scenarios. What is ideal for a small office may be excessive — or, conversely, insufficient — for a call centre or an online shop. Below, we share practical examples of what a balanced solution looks like for each of the typical formats.

● Small office (3-5 employees)

Telephony for small businesses does not require complex solutions. All you need is: one local number, a cloud-based PBX, internal extensions, simple call forwarding, and call recording. In terms of equipment, you will need softphones or one or two IP phones. Set-up takes literally just a day.

● Sales office (10-20 managers)

For this type of setup, the system includes: a multi-channel number or SIP trunk, IVR, call queues, call distribution among managers, call recording, statistics for each employee, and CRM integration. To ensure managers can work effectively, headsets or IP phones are provided at every workstation.

● Service provider or call centre

Telephony solutions for call centres are designed to handle large volumes of calls efficiently. In such environments, the key elements of telephony are: a 0800 number (customers call for free — more enquiries), queues with hold music, integration with Helpdesk/CRM systems, comprehensive analytics, and out-of-hours scenarios. Important metrics: waiting time, number of missed calls.

● Online shop

When it comes to telephony for online shops, there is one key requirement: integration with a CRM or order management system, so that when a call comes in, the customer and their order are immediately visible. A mobile client is used to make life easier for managers who are not always at their computers. Another important feature is call recording, which helps to quickly resolve disputes regarding orders or delivery.

Common mistakes when setting up a telephone system

Most problems with telephone systems arise not because of poor-quality equipment, but because of decisions made before the system is even launched. Here are the most common mistakes, which are easy to avoid if you are aware of them in advance:

1. Choosing a solution based solely on price or packaging. The cheapest PBX may not support the necessary integrations or have a limited number of channels. In a year’s time, you’ll have to replace the entire system — which is more expensive than getting it right from the start. The opposite extreme is no less dangerous: a slick presentation and a well-known brand do not guarantee cost-effectiveness. A solution that looks flawless in a demo may turn out to be excessively expensive when scaling the team or adding new features. Assess not your impression of the product, but the actual cost over a 2-3-year horizon.
2. Ignoring Internet quality. The most common mistake. As often happens: you’ve bought a good PBX, set it up — and calls are «falling through». The cause is almost always the network, not the telephony. Check the connection first.
3. Launching without routing logic. You have a number, but the call simply goes to a single phone. If the person is unavailable — the call is lost. Without routing, queues and call forwarding, the system does not protect against losing customers.
4. No contingency plan. What happens if the SaaS service goes down, your own server fails or the power goes out, and your telephony system relies on a hardware PBX? If there’s no solution, the phones go silent. In such cases, it is vital to have a mandatory Plan B: call forwarding to the on-duty staff member’s or department’s mobile number, a backup SIP trunk from another provider, a backup Internet connection, an answering machine, and a UPS (uninterruptible power supply) for the equipment.
5. Designing solely for current conditions. «There are five of us now, so this will be enough». A year later, there are twenty of us. And the old system can’t cope, or scaling it up is expensive. It’s better to choose a solution with room for growth right from the start.
6. Launching without training the team. The system is set up, but staff don’t know how to transfer a call. Half the features simply aren’t used. An hour’s training at launch pays for itself straight away.

Checklist: what you need to set up a telephone system in your office

Below is a practical checklist for setting up a telephone system in your office. It covers every stage, from preparatory decisions to final testing. It’s handy to print it out or save it and tick off the items one by one, so that no important step is overlooked in the process.

• ☐ Draw up technical specifications: set out system requirements, call handling scenarios, necessary integrations, expected load and acceptance criteria
• ☐ Choose a PBX model (cloud-based / on-premises / hybrid)
• ☐ Visualise the telephony diagram: what works with what and how
• ☐ Find a responsible technical contractor if there is no in-house expertise
• ☐ Select the type of numbers, forecast potential traffic, and find the best tariff terms from providers
• ☐ Check the Internet connection and the office LAN topology for workstations
• ☐ Select and purchase equipment (telephones, headsets, softphones)
• ☐ Configure internal numbers and call routing
• ☐ Configure IVR, queues and out-of-hours scenarios
• ☐ Set up call recording and statistics
• ☐ Integrate with CRM (if applicable)
• ☐ Prepare a backup plan (call forwarding / backup connection)
• ☐ Test the entire customer call flow
• ☐ Train the team to use the system

To sum up: office telephony is not an expense, but an investment in control and communication quality. A properly designed system ensures you never miss a single customer call, gives you a clear picture of your team’s performance, and allows you to scale up seamlessly. The key is to take a systematic approach to implementation: first understand your objectives, then choose the solutions — not the other way round.

If you want to figure out which solution is right for your business, the Maxnet team is ready to offer a consultation, assess your current communications setup, and suggest the best office telephony option. Without unnecessary technical complications and with a focus on your business.