The On-Premise PBX Decision

Despite the rise of hosted VoIP, many businesses across Belfast and Northern Ireland still prefer on-premise PBX systems. The reasons vary: some want complete control over their phone system, others have unreliable internet connections, and some simply prefer the reliability of hardware they own and can physically access.

If you've decided that an on-premise PBX is right for your business (and if you're not sure, read our comparison of hosted VoIP vs on-premise PBX), the two most popular choices in the UK market are Avaya IP Office and Panasonic's NS/NSX series. Here's how they compare.

Avaya IP Office: The Enterprise Contender

Avaya has been a major name in business communications for decades. The IP Office platform is their solution for small and medium businesses, sitting below their enterprise Aura platform.

Key Features

• Capacity: Supports up to 3,000 extensions across multiple sites (networked). A single system handles up to 384 extensions
• Unified Communications: Built-in UC features including presence, instant messaging, conferencing, and mobile integration via the Avaya Workplace app
• Contact Centre: Integrated contact centre functionality with skills-based routing, wallboards, and reporting — no separate system needed
• SIP trunking: Full SIP trunk support for connecting to modern VoIP providers
• Hybrid capability: Can operate as a pure on-premise system, a hybrid (on-premise with cloud features), or integrate with Avaya Cloud Office
• Voicemail Pro: Advanced voicemail with auto-attendant, call flows, and IVR menus
• Multi-site networking: Connect multiple offices with centralised management and inter-site calling

Avaya Handsets

Avaya offers their own range of IP phones (J139, J159, J169, J179, J189) as well as supporting third-party SIP phones from Yealink and others. Avaya's own phones integrate more tightly with IP Office features like visual voicemail and presence indicators.

Pricing

Avaya IP Office is a significant investment:

• Base system: £2,000-5,000 depending on configuration
• Per-user licensing: £50-150 per user depending on feature tier (Basic, Standard, Professional, Power User)
• Handsets: £100-350 per Avaya phone
• Annual maintenance: Typically 15-20% of system cost per year

A 20-user Avaya IP Office system with phones typically costs £8,000-15,000 installed, plus annual maintenance.

Panasonic NS/NSX Series: The Reliable Workhorse

Panasonic has been making business phone systems since the 1970s. Their NS700 and NSX series are the current on-premise offerings, known for reliability and simplicity.

Key Features

• Capacity: NS700 supports up to 288 extensions. NSX2000 supports up to 640 extensions across networked systems
• Hybrid design: Supports both traditional analogue/digital phones and modern SIP/IP phones on the same system
• DECT integration: Excellent built-in DECT support for cordless phones — ideal for warehouses, retail, and hospitality
• SIP trunking: Full SIP trunk support for modern VoIP connectivity
• Communication Assistant: UC software providing presence, call control, and CRM integration from the desktop
• Mobile integration: Mobile softphone app for making and receiving calls on your business number from your mobile
• Built-in voicemail: Integrated voicemail with auto-attendant and call routing

Panasonic Handsets

Panasonic offers a range of proprietary digital phones (KX-DT series) and SIP phones (KX-HDV series), plus DECT cordless handsets (KX-TCA/TPA series). The DECT phones are particularly popular — Panasonic's DECT implementation is among the best in the industry.

Pricing

Panasonic systems are generally more affordable than Avaya:

• Base system (NS700): £1,200-3,000 depending on configuration
• Per-user licensing: Lower than Avaya — many features included in the base system
• Handsets: £60-200 per Panasonic phone
• Annual maintenance: Typically 10-15% of system cost per year

A 20-user Panasonic NS700 system with phones typically costs £4,000-8,000 installed, plus annual maintenance.

Head-to-Head Comparison

• Scalability: Avaya wins. IP Office scales to 3,000 users across sites. Panasonic tops out at 640 with the NSX2000
• Unified Communications: Avaya wins. Built-in UC features are more comprehensive, especially the Workplace app and conferencing
• Contact Centre: Avaya wins decisively. Built-in contact centre with skills-based routing. Panasonic requires third-party solutions
• DECT/Cordless: Panasonic wins. Their DECT implementation is superior, with better range, more handset options, and easier management
• Simplicity: Panasonic wins. Easier to configure, manage, and maintain. Less training needed for administrators
• Cost: Panasonic wins. Significantly cheaper for equivalent user counts, with lower ongoing maintenance costs
• Reliability: Both are excellent. Panasonic has a slight edge for pure reliability — their systems are famously robust
• Hybrid (analogue + IP): Panasonic wins. Better support for mixing old analogue phones with new IP phones during migration
• Multi-site: Avaya wins. More sophisticated multi-site networking with centralised management
• Third-party integration: Avaya wins. More APIs, more CRM integrations, and broader ecosystem

Which Should You Choose?

The right choice depends on your business:

• Choose Avaya IP Office if: You have 30+ users, need contact centre features, want advanced UC capabilities, have multiple sites to connect, or need extensive CRM integration
• Choose Panasonic NS700 if: You have 5-50 users, need excellent DECT cordless coverage, want a simple and reliable system, are budget-conscious, or need to support existing analogue phones during migration

The Hosted VoIP Alternative

Before investing in either on-premise system, consider whether hosted VoIP might be a better fit. Hosted VoIP eliminates the large upfront cost, includes automatic updates, and works seamlessly with remote workers. For many businesses, especially those with under 50 users, hosted VoIP with Yealink handsets provides equivalent features at a lower total cost of ownership.

With the UK PSTN switch-off approaching in 2027, every business needs to move to IP-based communications regardless. The question is whether you want to own the system (on-premise PBX) or subscribe to it (hosted VoIP).

For a full breakdown of what you'll spend, see our guide on business phone system costs.

How Drakos Systems Can Help

At Drakos Systems, we supply, install, and maintain both Avaya and Panasonic PBX systems across Belfast and Northern Ireland. We also offer hosted VoIP solutions for businesses that prefer a subscription model. We'll assess your requirements — number of users, features needed, budget, and growth plans — and recommend the right solution. Whether that's an Avaya IP Office for your 100-person contact centre or a Panasonic NS700 for your 15-person office, we'll handle the entire project from design to installation to ongoing support.