1. What is VoIP and How Does It Work?

VoIP stands for Voice over Internet Protocol. In plain terms, it is a technology that converts your voice into digital data packets and sends them over the internet instead of through traditional copper telephone wires. When you speak into a VoIP phone, your voice is captured by the microphone, digitised using an audio codec, compressed into small data packets, and transmitted across your internet connection to the person you're calling. At the other end, the process reverses — packets are reassembled and converted back into sound.

The entire process happens in milliseconds. A properly configured VoIP system on a decent broadband connection delivers call quality that equals or exceeds a traditional landline. HD voice codecs like G.722 provide wideband audio that sounds noticeably clearer than the narrowband audio of PSTN phone lines — you can hear the difference immediately.

The Role of SIP

SIP — Session Initiation Protocol — is the signalling protocol that manages VoIP calls. It handles call setup, ringing, connecting, transferring, and disconnecting. Think of SIP as the traffic controller: it doesn't carry the voice data itself, but it tells the voice data where to go. When you dial a number on a VoIP phone, SIP establishes the session between your phone and the recipient's phone, negotiates which codec to use, and manages the call until one party hangs up.

SIP is an open standard, which means VoIP phones and systems from different manufacturers can communicate with each other. This interoperability is one of the key advantages of VoIP over proprietary telephone systems — you're not locked into a single vendor's hardware.

Codecs and Call Quality

A codec (coder-decoder) determines how your voice is digitised and compressed. Different codecs offer different trade-offs between audio quality and bandwidth usage. The most common VoIP codecs are G.711 (uncompressed, excellent quality, uses 87Kbps per call), G.722 (HD voice, wideband audio, uses 87Kbps), and G.729 (compressed, good quality, uses only 32Kbps per call). Most modern VoIP systems default to G.722 for HD voice quality, falling back to G.711 or G.729 when bandwidth is limited.

For businesses in Belfast and across Northern Ireland, the practical takeaway is straightforward: each simultaneous VoIP call needs approximately 100Kbps of bandwidth. A 10-person office where five people might be on calls at the same time needs at least 500Kbps dedicated to voice traffic. On a 100Mbps fibre connection, that's a tiny fraction of your available bandwidth — VoIP is not bandwidth-hungry.

Quality of Service (QoS)

The one technical requirement that separates a good VoIP deployment from a frustrating one is Quality of Service configuration. QoS is a setting on your router or firewall that prioritises voice traffic over other internet traffic. Without QoS, a large file download or a Windows update can consume all your bandwidth and cause VoIP calls to break up, echo, or drop. With QoS enabled, voice packets are always sent first, regardless of what else is happening on your network. Any competent VoIP provider will configure QoS as part of the installation — if they don't mention it, ask.

2. VoIP vs Traditional Phone Lines

The comparison between VoIP and traditional phone lines is no longer academic. With the UK's PSTN (Public Switched Telephone Network) being permanently switched off by January 2027, every business in the country must transition to internet-based telephony. The question is not whether to switch, but how to switch — and what you gain by doing so. For a detailed side-by-side comparison, see our guide on VoIP vs landlines in 2026.

Cost Comparison

Traditional phone lines cost £15–£25 per line per month for rental alone, before any call charges. ISDN2e lines cost £25–£40 per month for two channels. ISDN30 circuits cost £300–£600 per month for 8–30 channels. Call charges on top of these rentals add up quickly — national calls at 5–10p per minute, mobile calls at 10–15p per minute.

VoIP eliminates line rental entirely. Hosted VoIP costs £8–15 per user per month and typically includes unlimited UK landline and mobile calls. SIP trunking costs £3–8 per channel per month with call rates of 1–2p per minute to UK numbers. Most businesses that switch from traditional lines to VoIP see their phone bills drop by 30–60%. For a 20-person office paying £500/month on ISDN and call charges, the saving can be £200–£300 per month — every month, indefinitely.

Features

A traditional phone line gives you voice calls. That's it. Every additional feature — call forwarding, voicemail, caller ID, call waiting — costs extra and requires configuration by your provider. VoIP includes dozens of features as standard: auto-attendant, call recording, voicemail-to-email, call queues, ring groups, call analytics, mobile apps, video calling, presence indicators, and integration with your CRM and business applications. Features that would cost hundreds per month on a traditional system are included in the base VoIP subscription.

Flexibility and Scalability

Adding a traditional phone line means ordering a physical circuit from BT or your provider, waiting 2–4 weeks for installation, and paying for another monthly line rental. Adding a VoIP extension takes minutes — you provision it in the admin portal, plug in a handset or install a softphone app, and the new user is live. Scaling down is equally simple: you deactivate the extension and stop paying for it next month. For growing businesses in Belfast and Northern Ireland, this flexibility is transformative.

The PSTN Switch-Off

Openreach is switching off the PSTN and all ISDN services by January 2027. After that date, traditional analogue phone lines and ISDN circuits will cease to function. Every business in the UK must migrate to a VoIP-based solution before this deadline. Businesses that haven't started planning their migration are running out of time. The switch-off is not a future possibility — it is a confirmed, scheduled event with a hard deadline.

3. SIP Trunking Explained

SIP trunking is the bridge between your existing telephone system and the VoIP world. If you have an on-premise PBX (Private Branch Exchange) — whether it's an Avaya IP Office, a Panasonic KX-NS series, or any other IP-capable system — SIP trunks replace your ISDN lines and connect your PBX to the public telephone network over the internet. For a technical deep-dive, see our guide on what SIP trunking is and how it works.

How SIP Trunking Works

A SIP trunk is a virtual phone line delivered over your internet connection. Instead of physical ISDN circuits running into your building on copper or fibre, SIP trunks use your existing broadband or leased line to carry voice traffic. Your PBX connects to the SIP trunk provider's servers over the internet, and those servers connect to the public telephone network. Inbound calls to your business numbers are routed from the telephone network to the SIP provider, then down the SIP trunk to your PBX. Outbound calls travel the reverse path.

Channel Pricing

SIP trunks are sold in channels. Each channel supports one simultaneous call. If you need to handle 10 concurrent calls (inbound and outbound combined), you need 10 SIP channels. Pricing is typically £3–8 per channel per month, compared to £15–25 per ISDN channel. A business replacing a 30-channel ISDN30 circuit (costing £300–£600/month) with 30 SIP channels (costing £90–£240/month) saves immediately and significantly.

Number Porting

Your existing phone numbers — the numbers your customers know, the numbers printed on your business cards and website — transfer to the SIP trunk provider through a process called number porting. The porting process takes 1–4 weeks depending on the losing provider and the type of numbers being ported. During the port, your numbers continue to work on your existing lines. On the porting date, they switch seamlessly to the SIP trunks. Your customers dial the same numbers and notice no change whatsoever.

When SIP Trunking Makes Sense

SIP trunking is the right choice when you have a working, IP-capable PBX that you want to keep using, when you need to replace ISDN lines before the 2027 switch-off, and when you want to reduce line rental costs without replacing your entire phone system. It's a pragmatic, cost-effective migration path that preserves your existing investment in PBX hardware while moving you onto a future-proof platform. Many businesses across Northern Ireland are taking this approach — keeping their Avaya or Panasonic PBX and simply swapping ISDN for SIP trunks.

4. Hosted VoIP vs On-Premise PBX

This is the fundamental architectural decision in business telephony: do you run your phone system in the cloud (hosted VoIP) or on hardware in your own building (on-premise PBX)? Both approaches have legitimate advantages, and the right choice depends on your business size, technical resources, and priorities. For a detailed comparison, read our guide on hosted VoIP vs on-premise PBX.

Hosted VoIP (Cloud PBX)

With hosted VoIP, your phone system runs on servers in the provider's data centre. You don't own or maintain any PBX hardware. Your desk phones and softphone apps connect to the cloud platform over the internet. The provider handles all software updates, security patches, redundancy, and disaster recovery. You pay a per-user monthly fee that covers everything — the platform, features, support, and typically inclusive call bundles.

The advantages are compelling for most businesses. There is no upfront capital expenditure on PBX hardware. Scaling up or down is instant — add or remove users through an online portal. Remote and hybrid workers connect from anywhere with an internet connection, using the same phone system as office-based staff. The provider's data centres offer redundancy and uptime guarantees (typically 99.99%) that would be prohibitively expensive to replicate on-premise. Maintenance, updates, and security are the provider's responsibility, not yours.

On-Premise PBX

An on-premise PBX is a physical server or appliance installed in your building that runs your phone system locally. You own the hardware, and calls between internal extensions stay on your local network without touching the internet. Outbound and inbound calls connect to the public network via SIP trunks or, historically, ISDN lines.

On-premise systems offer maximum control. You own the hardware and the configuration. Call data stays on your premises. You're not dependent on a third-party cloud platform for your phone system to function. For businesses with strict data sovereignty requirements, on-premise can be the preferred option. However, the downsides are significant: capital expenditure of £2,000–£15,000+ for the PBX hardware, ongoing maintenance costs, the need for technical staff or a support contract to manage the system, and the risk that hardware failure takes your entire phone system offline.

Total Cost of Ownership

Over a five-year period, hosted VoIP typically costs less than on-premise for businesses with fewer than 50 users. The maths is straightforward: hosted VoIP at £12/user/month for 20 users costs £14,400 over five years with no hardware costs. An on-premise PBX costing £5,000 upfront plus £200/month for SIP trunks and maintenance costs £17,000 over the same period — and at the end of five years, the hardware needs replacing. For larger businesses with 100+ users, on-premise can become more cost-effective per user, but the management overhead and risk remain.

Our Recommendation

For the majority of businesses in Belfast and Northern Ireland — particularly those with 5–100 users — hosted VoIP is the right choice. It's cheaper, simpler, more resilient, and more flexible. On-premise PBX makes sense for large organisations with dedicated IT teams, specific compliance requirements, or existing PBX investments that still have useful life remaining (in which case, SIP trunking extends that life cost-effectively).

5. Key VoIP Features for Business

One of the most significant advantages of VoIP over traditional telephony is the sheer breadth of features included as standard. Features that cost extra on legacy systems — or weren't available at all — come built into every modern VoIP platform. Here are the features that matter most to businesses.

Auto-Attendant

An auto-attendant answers incoming calls with a professional greeting and routes callers to the right department or person using menu options. "Press 1 for Sales, Press 2 for Support, Press 3 for Accounts." It replaces the need for a dedicated receptionist to answer and transfer every call, and ensures calls are handled consistently even outside business hours. For small businesses in Belfast that want to project a professional image, an auto-attendant is invaluable.

Interactive Voice Response (IVR)

IVR takes the auto-attendant concept further. It can collect information from callers (account numbers, order references), provide automated responses (account balances, opening hours), and route calls based on complex rules. A well-designed IVR reduces the number of calls that need human handling and gets callers to the right person faster.

Call Recording

VoIP systems can record every call automatically — inbound and outbound. Recordings are stored in the cloud and searchable by date, number, user, or duration. Call recording is essential for compliance in regulated industries (financial services, legal), invaluable for training and quality assurance, and useful for resolving disputes. Most hosted VoIP platforms include call recording in their standard or mid-tier packages.

Call Queues and Ring Groups

Call queues hold callers in line when all agents are busy, playing hold music or position announcements. Ring groups distribute incoming calls across a team — simultaneously (all phones ring), sequentially (one after another), or round-robin (rotating through the team). These features ensure no call goes unanswered and workload is distributed fairly across your team.

Voicemail-to-Email

When a caller leaves a voicemail, the system converts it to an audio file and emails it to the recipient. Some platforms also provide voicemail transcription — converting the audio to text so you can read the message without listening to it. This means voicemails are never missed, even when staff are away from their desks or working remotely.

Mobile Apps and Softphones

Every major VoIP platform provides a mobile app that turns your smartphone into a full extension of your office phone system. You can make and receive calls on your business number, transfer calls to colleagues, access your company directory, and check voicemails — all from your mobile phone, anywhere with an internet connection. Desktop softphones do the same on your laptop or PC, eliminating the need for a physical desk phone entirely if you prefer.

Presence and Status

Presence indicators show whether colleagues are available, on a call, in a meeting, or away. Before transferring a call, you can check whether the recipient is free. This simple feature eliminates blind transfers to voicemail and reduces the frustration of callers being bounced between extensions.

Conferencing

Built-in audio and video conferencing allows multi-party calls without third-party services. Most VoIP platforms support conference bridges with 10–100+ participants, screen sharing, and recording. For businesses already using Microsoft Teams or similar platforms, VoIP conferencing integrates directly with your existing collaboration tools.

6. Microsoft Teams Integration

Microsoft Teams has become the default collaboration platform for businesses using Microsoft 365. Over 320 million people use Teams monthly worldwide. For many businesses in Northern Ireland, Teams is already where they chat, meet, share files, and collaborate. The logical next step is making Teams your phone system too — and VoIP makes that possible. For a complete walkthrough, see our guide on Microsoft Teams VoIP integration.

Direct Routing

Direct routing connects your VoIP provider's SIP trunks to Microsoft Teams, enabling Teams users to make and receive calls to and from external phone numbers. Your staff use the Teams app on their desktop, laptop, or mobile phone as their business phone. There's no separate phone system to manage, no additional hardware on desks, and no switching between applications. Calls, chats, meetings, and files all live in one interface.

How It Works

Your VoIP provider deploys a Session Border Controller (SBC) that connects their SIP trunk infrastructure to Microsoft's Phone System. Inbound calls to your business numbers are routed through the SBC into Teams. Outbound calls from Teams are routed through the SBC to the public telephone network. The SBC handles codec translation, security, and call routing. From the user's perspective, they simply click a phone number in Teams and the call connects.

Benefits for Hybrid Working

Direct routing through Teams is transformative for hybrid and remote working. Staff working from home use the same Teams app they use in the office. Their business phone number follows them — calls to their desk number ring on their laptop at home. They can transfer calls to office-based colleagues seamlessly. There's no VPN required, no separate softphone to install, and no compromise on call quality or features. For Belfast businesses with staff splitting time between the office and home, Teams telephony eliminates the friction of hybrid working entirely.

Microsoft Calling Plans vs Direct Routing

Microsoft offers its own calling plans (£6–£10/user/month) that provide PSTN connectivity without a third-party VoIP provider. However, direct routing through a VoIP provider typically offers lower call rates, more flexible number management, better support for complex call routing, and local expertise. For businesses in Northern Ireland, having a Belfast-based provider managing your Teams telephony means local support, local knowledge, and someone you can actually talk to when something needs attention.

7. CRM Integration

Connecting your VoIP phone system to your CRM (Customer Relationship Management) software is one of the highest-value integrations a business can make. It eliminates manual data entry, gives your team instant context on every call, and ensures every customer interaction is logged automatically. For implementation details, see our guide on CRM and VoIP integration.

Click-to-Dial

With CRM integration, your team can click any phone number in the CRM to initiate a call through the VoIP system. No manual dialling, no copying numbers, no misdials. This saves time on every call — and for sales teams making 50–100 calls per day, the cumulative time saving is substantial.

Screen Pops

When an inbound call arrives, the VoIP system looks up the caller's number in your CRM and displays their record on screen before you answer. You see the caller's name, company, account history, recent orders, open support tickets, and notes from previous conversations — all before you say hello. This transforms the customer experience. Instead of asking "Can I take your name and account number?", your team can say "Good morning, how can I help you today?" with full context already on screen.

Automatic Call Logging

Every call — inbound and outbound — is automatically logged in the CRM with the date, time, duration, caller number, and the team member who handled it. Call recordings can be attached to the CRM record. This eliminates the most common CRM adoption problem: staff forgetting (or choosing not) to log their calls. With automatic logging, your CRM becomes a complete, accurate record of every customer interaction.

Supported CRMs

Most modern VoIP platforms integrate with the major CRM systems: Salesforce, HubSpot, Microsoft Dynamics 365, Zoho CRM, Pipedrive, and many others. Some integrations are native (built into the VoIP platform), while others use middleware like Zapier or dedicated CTI (Computer Telephony Integration) connectors. The depth of integration varies — some offer basic click-to-dial and call logging, while others provide full screen pops, call disposition codes, and workflow automation.

For businesses in Northern Ireland using industry-specific CRMs (estate agency software, legal practice management, accountancy platforms), integration may require custom configuration. A good VoIP provider will assess your CRM during the sales process and confirm exactly what level of integration is achievable before you commit.

8. Call Centre and Contact Centre Features

VoIP platforms have made call centre functionality accessible to businesses of all sizes. Features that once required dedicated, expensive call centre platforms are now available as add-ons or included tiers within standard hosted VoIP systems. Whether you have a formal call centre with 50 agents or a small sales team of five, these features can transform how you handle calls. For metrics and KPIs, see our guide on call centre metrics that matter.

Advanced Call Queues

Call centre queues go beyond basic hold music. They provide estimated wait time announcements, position-in-queue updates, callback options (the system calls the customer back when an agent is free), overflow routing to other teams or external numbers, and time-based routing that changes queue behaviour outside business hours.

Wallboards and Real-Time Dashboards

Wallboards display live call centre metrics on screens visible to the team: calls waiting, average wait time, calls answered, calls abandoned, longest waiting call, and agent status. Supervisors can see at a glance whether the team is coping with call volume or whether additional resource is needed. Real-time dashboards in the admin portal provide the same data with historical trends and drill-down capability.

Skills-Based Routing

Skills-based routing directs calls to the agent best equipped to handle them. A caller selecting "Technical Support" is routed to agents tagged with technical skills. A caller speaking Irish is routed to an Irish-speaking agent. A VIP customer is routed to a senior account manager. This reduces transfers, improves first-call resolution, and ensures customers get expert help immediately.

Call Recording and Quality Management

In a call centre context, call recording serves multiple purposes: compliance (FCA-regulated firms must record certain calls), training (supervisors review calls with agents to improve performance), dispute resolution (a recording settles any disagreement about what was said), and quality scoring (calls are evaluated against criteria to maintain service standards). Modern platforms allow supervisors to listen to live calls, whisper coaching to agents (the caller can't hear), and barge into calls when intervention is needed.

Reporting and Analytics

Detailed reporting shows call volumes by hour, day, and week; average handling time; first-call resolution rates; agent performance comparisons; abandoned call rates; and service level achievement. This data drives staffing decisions, identifies training needs, and measures the impact of process changes. For businesses in Belfast running sales or support teams, these insights are the difference between guessing and knowing.

9. VoIP Handsets and Softphones

The physical (or virtual) device your team uses to make calls matters more than most businesses realise. The right handset or softphone improves call quality, productivity, and user satisfaction. The wrong choice creates frustration and undermines your entire VoIP investment. For detailed product comparisons, see our guides on Yealink phone setup and comparison and business softphones and WhatsApp integration.

IP Desk Phones

IP desk phones look and feel like traditional office phones but connect to your network via Ethernet rather than a phone line. They're powered by Power over Ethernet (PoE) from your network switch, eliminating the need for separate power adapters. Yealink is the market leader for SME VoIP handsets, and for good reason — their build quality, audio quality, and feature set are excellent at every price point.

• Entry-level (£60–£100): Yealink T31G or T33G — HD voice, 2–4 SIP accounts, basic display. Ideal for reception areas, warehouses, and staff who make occasional calls.
• Mid-range (£100–£180): Yealink T43U or T46U — colour display, Bluetooth, USB headset support, up to 16 SIP accounts. The workhorse for most office environments.
• Executive (£200–£350): Yealink T48U or T58W — large touchscreen, built-in WiFi and Bluetooth, camera option for video calls, up to 16 SIP accounts. For directors, managers, and heavy phone users.

DECT Cordless Phones

DECT cordless phones provide wireless mobility within your premises. A base station connects to your network, and cordless handsets communicate with the base station over DECT radio (not WiFi, so they don't compete with your data traffic). Yealink's W73H and W78H handsets paired with a W70B or W80B base station provide excellent range and call quality. DECT is essential for staff who move around — warehouse managers, retail floor staff, hotel reception teams, and anyone who can't be tied to a desk.

Softphones

A softphone is a software application that turns your computer or smartphone into a VoIP phone. Desktop softphones run on Windows or Mac and use your computer's microphone and speakers (or a USB headset) for calls. Mobile softphones run on iOS and Android and use your phone's hardware. The advantage of softphones is zero hardware cost — your team uses devices they already have. The disadvantage is that call quality depends on the device's microphone and speakers, and a headset is strongly recommended for professional use.

Headsets

Whether your team uses desk phones or softphones, a quality headset transforms the calling experience. Wireless Bluetooth headsets from Jabra (Evolve2 series) and Poly (Voyager series) provide freedom of movement, noise cancellation for open-plan offices, and all-day comfort. For call centre environments, wired USB headsets offer reliability and consistent audio quality. Budget £40–£150 per headset depending on features — it's one of the best investments you can make in call quality and staff comfort.

10. ISDN to VoIP Migration

If your business currently uses ISDN lines — whether ISDN2e (BRI) for small offices or ISDN30 (PRI) for larger systems — you must migrate to VoIP before the PSTN switch-off in January 2027. This is not optional. Openreach will decommission all ISDN services, and your lines will stop working. For the full timeline and implications, see our guides on the ISDN switch-off 2027 and the UK PSTN switch-off.

ISDN2e (BRI) Migration

ISDN2e provides 2 channels (2 simultaneous calls) per circuit. Small businesses typically have 1–4 ISDN2e circuits, giving them 2–8 channels. Migration is straightforward: replace the ISDN2e circuits with SIP trunks (if keeping your PBX) or move to hosted VoIP (if replacing the entire system). The number of SIP channels you need matches the number of ISDN channels you currently use. Your phone numbers port across seamlessly.

ISDN30 (PRI) Migration

ISDN30 provides 8–30 channels on a single circuit and is used by medium to large businesses with significant call volumes. Migration from ISDN30 to SIP trunking is the most common path — it preserves your existing PBX and simply replaces the ISDN connectivity with SIP. The cost saving is immediate: an ISDN30 circuit costing £400/month can be replaced with equivalent SIP channels for £100–£200/month.

Avaya Migration

Avaya IP Office is one of the most widely deployed PBX systems in Northern Ireland and the UK. If you have an Avaya IP Office 500 V2 or later, it supports SIP trunking natively — you can replace your ISDN lines with SIP trunks and keep using your Avaya system. If your Avaya system is older or reaching end of life, migration to hosted VoIP provides a modern, fully supported platform with lower ongoing costs. For a detailed comparison of migration paths, see our guide on Avaya vs Panasonic PBX systems.

Panasonic Migration

Panasonic KX-NS and KX-TDE series PBX systems are equally common across Northern Ireland businesses. The KX-NS700 and KX-NS1000 support SIP trunking with the appropriate licence cards. Older Panasonic systems (KX-TDA series) may require a gateway device to connect SIP trunks. As with Avaya, the decision is whether to extend the life of your Panasonic system with SIP trunks or migrate to a hosted VoIP platform. Both paths are valid — the right choice depends on the age and condition of your hardware, your budget, and your appetite for change.

Migration Timeline

A well-planned VoIP migration takes 4–8 weeks from decision to go-live. The process follows a predictable sequence: site survey and requirements gathering (week 1), system configuration and number porting request (weeks 2–3), hardware delivery and installation (week 3–4), testing and user training (week 4–5), go-live and number port completion (weeks 5–8). The number porting process is typically the longest single step, as it depends on the losing provider releasing your numbers. Starting early gives you buffer time for any delays.

11. VoIP Costs Breakdown

Understanding VoIP costs requires looking beyond the headline per-user price. There are several cost components, and transparency from your provider on all of them is essential. For detailed pricing analysis, see our guides on business phone system costs and VoIP installation costs in Northern Ireland.

Hosted VoIP Per-User Costs

SIP Trunking Costs

Hardware Costs

Installation and Setup

Professional installation typically costs £200–£800 depending on the number of handsets, network configuration required, and whether QoS and VLAN setup is needed on your switches and router. Some providers include installation in the contract; others charge separately. Always ask for a fully itemised quote that includes installation, configuration, number porting, and user training.

Total Cost of Ownership Example

A 20-user business in Belfast switching from ISDN to hosted VoIP might see costs like this: 20 mid-range handsets at £130 each (£2,600), installation and configuration (£500), monthly hosted VoIP at £12/user (£240/month). Total first-year cost: £6,380. Compare that to their existing ISDN setup: line rental £300/month, call charges £150/month, maintenance contract £100/month — £6,600 per year with no new features. The VoIP system pays for itself within the first year and saves £3,000+ every year after that.

12. Choosing the Right VoIP Provider

The VoIP market in the UK is crowded. Dozens of providers compete for your business, and the quality varies enormously. Choosing the wrong provider means poor call quality, unreliable service, and frustrating support experiences. Here's what to look for — and what to avoid. For provider comparisons, see our guides on the best VoIP providers in the UK and the best VoIP for small businesses.

What to Look For

• UK-based support: When your phones go down at 9am on a Monday, you need to speak to someone who understands your system, speaks your language, and can fix the problem quickly. Offshore support centres reading from scripts are not acceptable for business-critical telephony.
• Uptime SLA: Look for 99.99% uptime guarantees backed by financial penalties if the provider fails to deliver. Ask where their platform is hosted — UK data centres with geographic redundancy are the minimum standard.
• Number porting experience: Porting numbers is the most common source of migration problems. Ask how many ports the provider handles per month and what their success rate is. An experienced provider manages the entire porting process and keeps you informed at every stage.
• Transparent pricing: The per-user price should include all features you need. Watch for hidden costs: call recording storage fees, auto-attendant charges, additional charges for mobile apps, per-minute call rates on top of the subscription. Get a fully itemised quote before signing anything.
• Integration capability: If you use Microsoft Teams, a CRM, or other business applications, confirm that the provider supports integration before you commit. Ask for a demonstration, not just a promise.
• Contract flexibility: Avoid long-term contracts (36 months) with heavy early termination fees. The best providers offer 12-month or even monthly rolling contracts because they're confident you'll stay based on service quality, not contractual obligation.

Red Flags

• No site survey offered: A provider that quotes without understanding your network, broadband speed, and requirements is guessing. A professional provider always surveys before quoting.
• Pressure to sign quickly: "This price is only available today" is a sales tactic, not a genuine offer. Walk away from any provider that pressures you into a decision.
• No mention of QoS: If the provider doesn't discuss Quality of Service configuration during the sales process, they either don't understand VoIP networking or don't care about your call quality. Either way, avoid them.
• Vague SLA: "We guarantee high availability" means nothing. You need specific percentages, specific repair times, and specific compensation terms in writing.
• No references: A good provider will happily connect you with existing customers in your area or industry. If they can't or won't provide references, ask yourself why.

Questions to Ask

Before choosing a provider, ask these questions: Where is your platform hosted and what redundancy do you have? What is your uptime SLA and what compensation do you offer if you breach it? Who provides technical support and what are your support hours? How do you handle number porting and what is your typical timeline? Can you demonstrate CRM integration with our specific CRM? What happens if we want to leave — what are the exit terms and do we keep our numbers? Can you provide references from businesses similar to ours in Northern Ireland?

13. How Drakos Systems Can Help

Drakos Systems is a Belfast-based technology provider that has been helping businesses across Northern Ireland and the UK with their phone systems for over 20 years. We don't just sell VoIP — we design, deploy, and support complete business telephony solutions tailored to your specific requirements.

Hosted VoIP

Our hosted VoIP platform provides enterprise-grade telephony for businesses of all sizes. HD voice quality, 99.99% uptime SLA, auto-attendant, call recording, call queues, mobile apps, and CRM integration — all included. We handle everything from the initial site survey through to installation, number porting, user training, and ongoing support. Whether you're a five-person office in Belfast city centre or a 200-seat contact centre in Lisburn, we scale the solution to fit.

SIP Trunking

For businesses with existing PBX systems that still have useful life, our SIP trunking service replaces your ISDN lines with cost-effective, reliable SIP channels. We support Avaya IP Office, Panasonic KX-NS series, and all major IP-capable PBX platforms. Number porting is managed end-to-end by our team, and we configure QoS on your network to ensure call quality from day one.

Avaya and Panasonic Migration

We have deep expertise in migrating businesses from legacy Avaya and Panasonic systems. Whether you're adding SIP trunks to extend the life of your existing PBX or migrating entirely to hosted VoIP, we've done it hundreds of times. We understand the configuration nuances of these platforms and can plan a migration that minimises disruption to your business.

Microsoft Teams Integration

We deploy direct routing for Microsoft Teams, turning your existing Teams environment into a full business phone system. Our engineers handle the SBC configuration, SIP trunk provisioning, number porting, and Teams Phone System licensing. Your staff get a single application for calls, chats, meetings, and collaboration — with full PSTN connectivity to external numbers.

24/7 Support

Our support team is based in Belfast and available around the clock. When your phones are your business, you need support that responds immediately — not a ticket system that promises a reply within 24 hours. We provide proactive monitoring of your VoIP platform and can often detect and resolve issues before you notice them.

ISO 27001 Certified

Our ISO 27001 certification means our processes, systems, and data handling meet the highest international standards for information security management. For businesses in regulated industries — financial services, healthcare, legal — this certification provides assurance that your telephony provider takes security as seriously as you do.

Free Site Survey

Not sure where to start? We offer a free, no-obligation site survey. Our engineers will assess your current phone system, test your broadband for VoIP readiness, review your network infrastructure, and recommend the right solution for your business. Whether you're in Belfast, Derry, Newry, Lisburn, or anywhere in Northern Ireland, we'll come to you.

14. Frequently Asked Questions