IP telephony for business: how it works
IP telephony carries voice over the data network instead of traditional phone lines. For a business, that means more features, more mobility and one network for everything.
The building blocks
- IP phone system (PBX): the brain that routes calls to extensions, queues and menus. It can be in the cloud or on a device in the office.
- Extensions: every phone, app or desk has its own internal number.
- Endpoints: desk phones, DECT cordless handsets, mobile apps (softphones) or computers.
- Connection to the outside world: the phone system connects to your operator's lines, usually through a SIP trunk.
SIP, the common language
SIP is the standard protocol used to set up IP calls. If a phone, a phone system or a video intercom is SIP-compatible, they can work together even from different manufacturers.
Advantages
- Welcome menus, queues, schedules and automatic diversions.
- Your office extension on your mobile, including when working remotely.
- Several sites joined up as one.
- Statistics: missed calls, waiting times, peak hours.
- Integration with video intercoms, paging and, where relevant, the CRM.
What you need
- A network that prioritises voice and PoE switches for the phones.
- A stable internet connection and, if critical, a backup.
- A UPS for the network and the phone system.
- A numbering plan and call flow designed around the business.
An IP call, step by step
- The customer dials your number and the call reaches the phone system over the operator's line.
- The phone system checks the time and applies the rules: welcome menu, ring group or queue.
- Desk phones ring, mobile apps ring, or both.
- If nobody answers, the call moves to the next destination: another group, a mobile or voicemail.
- It's logged in the statistics.
What migration looks like
- Inventory: numbers, extensions, current call flow and equipment to keep.
- Network: checking cabling, PoE switches and voice priority.
- Parallel setup: the new phone system is prepared and tested without touching the old one.
- Switchover: at a quiet time, the lines move to the new system.
- Fine-tuning: over the first few days, menus, hours and groups are adjusted.
How much bandwidth is needed
A voice call uses little: around 100 kbps per conversation with common codecs. What matters isn't quantity but stability, and voice having priority over other traffic.
Security
- Strong passwords on extensions and phone system administration.
- Don't expose the phone system directly to the internet; use encrypted remote access or a VPN.
- Restrict international destinations if you don't use them, to prevent toll fraud.
- Keep phone system and handset firmware up to date.
Which phone for which role
- Reception: a handset with plenty of keys to see and transfer extensions.
- Office desks: a standard phone or a softphone with a headset.
- Staff on the move: DECT.
- Management and meeting rooms: video handsets or conference units.
Frequently asked questions
Is the quality worse than a traditional line?
Not if the network is properly set up. With high-definition codecs, voice often sounds clearer. Quality problems almost always come from a network that doesn't prioritise voice.
Can I start with a few phones and expand?
Yes. An IP phone system grows by adding extensions and handsets; there's no need to change system as you add people or sites.
What about emergency calls?
They must always work. They're configured explicitly in the phone system and tested during commissioning.
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Tell us about your project
We look at what you need and propose a complete solution: one company, one point of contact, one project.
- Phone+376 356 249
- Emailinfo@knxandorra.com