Industry · Contact centres
Inbound connectivity for contact-centre platforms
Customers judge a contact centre on whether they get through and whether they can hear. We deliver your numbers to your contact-centre platform over SIP, number by number, with failover and call quality planned alongside your routing.
- Number-by-number routing
- Toll-free and local numbers
- Platform failover
Inbound first
How an inbound call reaches an agent
Most contact-centre traffic is inbound. The trunk’s job is to deliver every call to your platform quickly and with the information the platform needs to route it.
- A customer dials a published number, for example a toll-free sales line or a local support number.
- The carrier network routes that number to your SIP trunk.
- The trunk delivers the call to your contact-centre platform over SIP, with the dialled number and caller ID in the agreed format.
- The platform reads the dialled number and applies its own logic: IVR menu, skills-based queue, opening hours or customer lookup.
- An available agent answers, wherever they are working, or the call follows the overflow rules set on the platform.
Omnichannel platforms handle voice alongside email, chat and messaging. Voice reaches them through a SIP connection, and the platform brings all channels together in one agent desktop. We are concerned with the voice part: the numbers, the SIP connection and what happens if the platform cannot be reached.
Responsibilities
What the trunk does and what your platform does
IVR menus, queues and overflow logic stay on your contact-centre platform, where your team already manages them. This table shows where each function sits.
Division of functions between the SIP trunk and the contact-centre platform
-
Numbers and number routing
- SIP trunk and numbers
- Provisioned and routed to your platform, number by number
- Your contact-centre platform
- Assigned to the right entry point or flow
-
IVR menus and announcements
- SIP trunk and numbers
- Not involved; audio and DTMF are passed through intact
- Your contact-centre platform
- Designed and run on the platform
-
Queues, skills and agent states
- SIP trunk and numbers
- Not involved
- Your contact-centre platform
- Configured and reported on the platform
-
Overflow when agents are busy
- SIP trunk and numbers
- Not involved
- Your contact-centre platform
- Rules on the platform, for example to another team or site
-
Failover when the platform is unreachable
- SIP trunk and numbers
- Calls sent to an agreed alternate destination
- Your contact-centre platform
- Alternate destination prepared to receive calls
-
Call recording
- SIP trunk and numbers
- Not involved by default
- Your contact-centre platform
- Recording, storage and retention, where enabled
Numbers
Toll-free and local numbers for each line of business
A contact centre often publishes many numbers: one per brand, product, region or campaign. Each one is routed individually.
- Toll-free numbers let customers call without charge; the receiving organisation pays inbound per-minute costs, which vary by country and by the caller’s network.
- Local and national numbers give a regional presence and are usually cheaper to receive.
- Each number can be sent to a different entry point on your platform, so reporting by line of business is accurate from the first ring.
- Existing numbers can often be ported. New numbers may require address or business documentation, depending on the country.
Overflow and failover
Overflow and failover are different problems
Both keep callers from being turned away, but they are solved in different places.
Overflow: agents are busy
When queues are full or waits are too long, your platform decides what to do: offer a callback, route to another team, or send calls to an outsourced partner. These rules are set on the platform and can change during the day.
Failover: the platform cannot be reached
If the platform or its network is unavailable, it cannot make any decision. In that case the trunk sends inbound calls to an alternate destination agreed in advance, such as a second platform instance, a backup site or a number that plays an announcement. We test this before go-live and after significant changes.
Call quality
Call quality for agents in several locations
Poor audio lengthens calls and lowers satisfaction scores. Most quality problems are found on the path between the agent and the platform.
-
Codecs
G.711 avoids transcoding and keeps speech clear for agents and speech analytics. Other codecs are agreed only where the route and platform both support them.
-
Jitter and packet loss
Uneven packet arrival causes choppy audio. Prioritise voice on every network the call crosses, including agent home connections, and keep jitter buffers set sensibly on softphones.
-
DTMF for IVR
IVR menus and payment flows depend on keypad tones arriving reliably. DTMF method is matched on the trunk and the platform, then tested on every menu.
-
Multi-site and remote agents
Agents in several offices or at home register to the same platform. Each location needs enough bandwidth and a stable path; the trunk itself does not change.
Call recording
Call recording obligations
Recording is normally carried out on your contact-centre platform. The obligations that come with it belong to the organisation that records: telling callers that calls are recorded, obtaining consent where the law requires it, pausing recording while card details are taken, and storing and deleting recordings according to your retention policy and data protection law.
Rules differ between countries and sectors. Confirm your obligations with your compliance team or legal adviser. We can explain what call data passes through our service; our privacy policy describes how we handle it.
Recommended services
Services contact centres usually combine
FAQ
Questions from contact centre teams
Which contact-centre platforms can connect?
Platforms that accept a standard SIP trunk can usually connect, whether hosted or self-managed. Some hosted platforms use their own carrier connection or a specific integration method, so we review your platform’s requirements before you commit.
Can each number go to a different queue?
Yes. Each number is delivered with the dialled number intact, so your platform can send every number to its own flow. That is how one platform can serve sales, support and several brands or regions.
What happens if our platform has an outage?
Inbound calls can be routed to an alternate destination you choose, such as a second platform, a backup site or a recorded announcement on another system. The destination is agreed in advance and tested before go-live.
Can we keep our existing toll-free numbers?
Often yes, through porting. Toll-free porting rules vary by country and current provider, and a letter of authorisation is required. We check portability before you give notice to anyone.
Next step
Connect your contact-centre platform
Tell us which platform you use and which numbers customers call. We will reply with compatibility notes, a number routing plan and an itemised quote.
Helpful to include
- Contact-centre platform and how it accepts SIP
- Numbers to port or order, by country and type
- Peak concurrent calls in the busiest hour
- Agent locations, including home workers
- Preferred failover destination