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Demo

Telephony

SIP telephony for contact centers

You keep your current numbers and carriers, while calls get queued and recorded the way a real contact center handles them. Agents talk on whatever device suits them – a browser, an IP phone, or a gateway, in the office or at home. Add a second carrier, and customers still get through when your main one goes down. We connect your numbers over SIP trunks and set up routing, encryption, and devices. Supported protocols: SIP, PJSIP, H.323, and WebRTC.

Get a quotePricing
4protocolsSIP, PJSIP, H.323, WebRTC
Anydevicebrowser, phone, gateway
Backupsecond trunkin case of an outage
$0line licensesyou pay for setup

Features

What SIP telephony includes

Carrier SIP trunksConnect numbers from one or more carriers over trunks, with a separate call path for each number.
Browser-based softphoneAgents take calls in a browser tab over WebRTC, with nothing to install on their computers.
IP phones and gatewaysDesk phones and VoIP gateways register on the platform over SIP or PJSIP.
Legacy H.323 equipmentOlder phones connect directly: they get calls on equal terms with every other device, and those calls are recorded too.
Call encryptionTLS protects signaling, SRTP protects the audio, and password-guessing attempts from unknown addresses are blocked.
Calls behind NATSTUN and TURN help audio get through remote agents' home routers and firewalls.

Examples

What it looks like in practice

Three situations that most often bring contact centers to us.

A number from another carrier, with no changes for agents

A company starts selling in a new region and buys a local number from a different carrier. The carrier sends the connection details, we add the trunk to the platform, and calls to the new number go to the sales queue. Agents don't reconfigure anything – calls from the new line simply show up.

  • The trunk registers on the platform
  • A dedicated route for the number
  • No changes on the agent side
Example 1 of 3

If a number moves to a new carrier, the carrier handles the porting, and it takes more than a day.

How it works

Protocols, audio, and network

Protocols

SIP, PJSIP, H.323, and WebRTC

SIP and the modern PJSIP stack handle trunks, IP phones, and gateways. H.323 serves equipment you already own, such as video endpoints in meeting rooms. WebRTC enables calling from a browser and embedding calls in your website or app.

  • Trunks and phones – SIP and PJSIP
  • Legacy equipment – H.323
  • Browsers and apps – WebRTC

Audio

Codecs matched to your connection

Inside the office network, calls use G.711 for the best audio. Opus suits browsers and mobile devices: it uses less bandwidth and holds up well under packet loss. If a call sounds choppy, the first thing we check is packet loss and latency between the agent and the platform.

  • G.711 in the office
  • Opus for browsers and mobile
  • Packet loss and latency checks

Network

Audio gets through NAT and firewalls

Remote agents sit behind home routers, where audio often drops in one direction. STUN detects the public address, TURN relays audio when the direct path is blocked, and ICE picks a working route. On the platform side, only the required SIP and RTP ports are open.

  • STUN, TURN, and ICE
  • Only the ports you need
  • Works from any network
Same numbers, same contractsNo need to switch carriers or give customers a new number: calls to the numbers they already know start flowing into your queues.
Agents work from anywhereOffice, home, or a branch – agents answer in the browser or on an IP phone, and call routing and recording work the same for everyone.
Customers get through during outagesA second carrier picks up the calls if your main one has a failure, so the line never goes silent.
Keep your existing hardwareVideo endpoints and H.323 phones keep working, so you don't have to buy replacements.

Setup

How we set up SIP telephony

  1. 01NumbersWe list every number with its carrier and decide whether you need a backup carrier. Customer-facing numbers stay the same.
  2. 02TrunksWe add your carriers' trunks to the platform and test each one with inbound and outbound calls.
  3. 03RoutingFor each number, we set where it goes: the IVR, a queue, or a specific agent.
  4. 04DevicesWe connect browsers, desk phones, and gateways, updating firmware if needed – agents keep the hardware they're used to.
  5. 05SecurityWe turn on encryption and block access from unknown addresses, so nobody can eavesdrop on calls or hijack your numbers.
  6. 06TestingWe check call audio from the office, from an agent's home, and over mobile data. We move all lines over only once the quality is right.

Requirements

What you need for SIP telephony

Carrier
Any carrier that offers SIP trunking
Protocols
SIP, PJSIP, H.323, WebRTC
Devices
Browser, IP phones, VoIP gateways
Network
A stable internet connection or a direct link to the carrier
Hosting
A cloud server or your own
Price
No per-line licenses; you pay only for setup hours

Preparation

What we need from you

Which numbers to connect?Which numbers, and with which carriers.
Do you have trunk details?Addresses, usernames, and passwords from your carriers.
Do you need a backup?A standby trunk from another carrier.
Which devices?Browser, IP phones, gateways, H.323.
Where are your agents?Office, home, or several locations.
Who will configure routers?The admin for your routers and firewall.

Q&A

Frequently asked questions

Do we need to change our numbers or carrier?

No. Your carrier provides a SIP trunk, and calls to your numbers start arriving on the platform. Customers dial the same numbers as before.

Carriers →

Can we connect several carriers?

Numbers from different carriers land in shared queues, and each one gets its own route.

What happens if a carrier has an outage?

With a backup trunk, calls go to the second carrier, and customers can still reach you. Without one, that carrier's numbers stay unreachable until it fixes its network.

Can we keep our existing hardware?

H.323 video endpoints and phones work with the platform, so you don't have to replace them right away.

Do we need to buy IP phones?

Not necessarily: a headset and a browser are enough. We connect IP phones if you already have them or your agents prefer them.

Browser-based softphone →

What does an agent need to work from home?

A stable internet connection and a headset. Audio passes through the home router thanks to STUN and TURN, and queues and recording work for remote agents just as they do in the office.

How are calls protected?

Calls are encrypted, and password-guessing attempts from unknown addresses are blocked. You can also restrict platform access to your company's IP addresses.

Data security →

Can we call customers from a mobile number?

Through a cellular gateway with your company's SIM cards – the customer sees a mobile number.

Cellular gateways →

Will our toll-free numbers and numbers in other cities work?

They will: your carrier provides them, and we give each one its own route.

Which protocols do you support?

SIP and PJSIP for trunks and phones, H.323 for older equipment, and WebRTC for calling from a browser.

Can the system handle our call volume?

We size carrier lines and server capacity for your busiest hour. The platform handles 2.75M calls every day, so the key is getting the line count right.

Which number do customers see when we call?

Whichever one you assign to the line or department: a local number, a toll-free number, or a number in the customer's region.

How much does SIP telephony cost?

There's no per-line fee. Setup work is billed under your support plan, hosting applies if you choose our server, and minutes and numbers are paid to your carrier.

Pricing calculator →

Glossary

Terms on this page

SIP (Session Initiation Protocol)
The protocol that sets up calls in IP telephony. Learn more →
WebRTC
Calls right from the browser, with nothing to install. Learn more →
Backup
Data is regularly copied to a separate place so it can be restored if something goes wrong. Learn more →
Encryption
Encrypted data can't be read without the key. Learn more →
SIP trunk
A phone line from the carrier over the internet instead of a wire. Learn more →
Softphone
A phone app that runs on a computer or in a browser. Learn more →
Hosting
You rent a server from a provider instead of buying one. Learn more →
Call routing
Rules the system uses to decide who gets a call. Learn more →
VPN
An encrypted tunnel from the internet into an internal network. Learn more →
IVR (interactive voice response)
A phone menu: the caller hears a greeting and picks the right department. Learn more →
Cloud deployment (cloud)
The platform runs on the vendor's servers, and agents connect over the internet. Learn more →

More

More on telephony

Telephony Inbound lines, outbound campaigns, and a browser phone for agents, all connected to your CRM. Learn more Cellular gateways Work cell numbers as contact center lines. Learn more Browser softphone Agents need only a browser and a headset – no phones, no software. Learn more Call recording Replay any customer conversation whenever you need it. Learn more

Blog

Fresh from the blog

All articles →
Services · 7 min read Custom development of your contact center platform for your processes When contact center settings are not enough: integrations, modules, AI workflows. How to tell development from configuration and estimate the payback. Read the article → Management · 9 min read How many agents does your contact center need? Erlang C in plain English Calculate contact center staffing with Erlang C: workload, service level, shrinkage, and headcount by shift – all in one worked example. Read the article → Integrations · 7 min read CRM and phone system integration: what it does and how it works How to connect your phone system to your CRM: calls and recordings in the record, screen pop, click-to-call. What to decide first and how to check it works. Read the article →

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