Your PBX investment stays in service
The licences, extensions, dial plan and staff habits you already have keep working. Only the connection to the outside world changes.
SIP Trunking
Keep your PBX. Change what it connects to.
3CTel SIP trunks connect a 3CX, FreePBX, Asterisk or on-premise PBX to the public phone network in Canada — with the channel count, DIDs, caller ID and failover rules your system expects, and a quote based on how many calls you actually run at once.
- Works with 3CX, FreePBX and on-premise PBX systems
- Canadian local and toll-free DIDs, ported or new
- Failover when your PBX is unreachable
Example
Site A
Site B
Mobile
Your PBX or apps
3CTel SIP trunks
Call quality: HD
Carrier network
3CTel SIP Trunking connects a PBX you already own to the public phone network over the internet, replacing copper lines or a PRI circuit. Channels are sized to your peak concurrent calls, Canadian local and toll-free DIDs are pointed at the trunk, and inbound calls fail over to a number you choose if the PBX goes offline. It suits businesses that want to keep their 3CX or on-premise system while modernizing connectivity.
What changes for your business.
You pay for concurrent calls, not phone lines
Channels are sized to your busiest hour rather than to the number of desks. Add channels for a seasonal peak and remove them afterward.
Every number you publish comes with you
Main lines, direct lines, fax numbers and toll-free numbers port to the trunk. The old service stays live until the port date the carriers confirm.
Callers still reach someone when the PBX is down
If your PBX loses power, internet or registration, inbound calls follow a forwarding path you set in advance instead of ringing into nothing.
Core capabilities.
Registration or IP-authenticated trunks
Trunks authenticate by SIP credentials or by your PBX’s public IP address, whichever your system and firewall arrangement suit. Both options are tested with your administrator before cutover.
Channels sized to concurrent calls
A channel is one live call. Channels are separate from DIDs: ten numbers can share four channels if that is what your traffic needs. We review your peak before setting the count.
Canadian local and toll-free DIDs
Direct inward dialling numbers in Canadian rate centres, plus toll-free numbers, delivered to your PBX with the DID in the header so your system can route each number differently.
Number porting to the trunk
Single lines, hunt groups, DID blocks and toll-free numbers port from your current carrier onto the trunk. Porting timelines are set by the carriers involved and confirmed with you before anything switches.
Caller ID presentation
Outbound caller ID is set per trunk or per call from the numbers you own, so a branch can show its local number and a support team its toll-free line. Withheld caller ID is supported where the PBX requests it.
Codec options
G.711 for full-quality audio on capable connections, G.729 where bandwidth per call matters more. Codec preference is agreed with your PBX administrator and matched on both sides.
Failover and forwarding
When the trunk cannot reach your PBX, inbound calls forward to a mobile, another site or a cloud voicemail. Failover targets are set per DID and can be changed without touching the PBX.
Fraud controls
Optional per-trunk limits on call rate, spend and destinations, and international dialling that is restricted by default. Controls are chosen with you so legitimate traffic is not blocked.
Common use cases.
A company running 3CX on its own server
Trunks are configured against the settings your 3CX installation expects, tested on a temporary DID, then the published numbers port across on a confirmed date.
An IT team with FreePBX or Asterisk
Your team keeps full control of the dial plan. We provide trunk credentials, codec preferences and the DID format, and verify inbound and outbound calls with you.
An on-premise PBX behind a SIP gateway
Older systems that speak SIP through a gateway or session border controller connect the same way. We check what the gateway supports before quoting channels.
Multiple sites sharing one trunk group
A head office and branches share channels and a DID range on a single account, with per-DID failover so a branch outage does not affect the others.
AI conversation intelligence on trunk calls
Calls that pass over 3CTel trunks to your own PBX can be recorded and analysed by conversation intelligence, giving your team summaries, transcripts and keyword flags without changing your dial plan; scope and consent announcements are agreed during planning.
Setup and migration.
Most SIP trunk problems come from mismatched settings discovered on cutover day. The steps below surface them earlier, while your current service is still carrying calls.
Document the PBX and the traffic
We record the PBX type and version, public IP or registration method, peak concurrent calls, the numbers to port and the 911 service address for each site.
Build the trunk and a test DID
Trunks are provisioned with the agreed channel count, codecs and authentication. A temporary DID lets your administrator test inbound, outbound, transfers and caller ID with nothing live yet.
Set failover and controls
Forwarding targets per DID, rate and destination limits, and caller ID rules are configured and reviewed with you before the port is scheduled.
Port and monitor
Numbers move on the date the carriers confirm. The old carrier keeps working until then, and we watch the first days of live traffic with your team.
AI in this product
AI on your SIP trunks
Trunk traffic and quality are analyzed continuously so capacity, cost and network issues are raised with evidence before they become outages.
Quality hot-spot detection per trunk and site
Jitter, packet loss and latency are tracked per call and correlated with trunk, site, time of day and network path, so a recurring degradation is traced to its cause.
Channel capacity and concurrency review
Peak concurrent calls per trunk are compared with the channels you pay for, and the recommendation names whether and when capacity should be added or reduced, with the peaks behind it.
Toll fraud and anomaly alerts
Unusual outbound patterns on a trunk, such as overnight international bursts or repeated calls to premium numbers, are flagged with proposed limits that apply only once you approve them.
Common questions, answered directly.
When does SIP trunking make more sense than a hosted phone system?
When the PBX is recent, paid for and doing its job, and the problem is the lines feeding it. SIP trunks cut the cost of PRI or analog circuits and add capacity without new hardware, while extensions, licences and staff habits stay put. When the PBX itself is ageing or unsupported, a hosted system is usually the better move, and both can be discussed in one planning call.
How many SIP channels does a business need?
One channel per call you expect to hold at the same time, inbound and outbound combined, at the busiest hour. Call records from the current system or a short measurement period give a real peak; a margin is then added for growth and for outbound campaigns. Channels can be adjusted after activation, so the first number does not have to be perfect.
What settings does a PBX administrator need to connect a SIP trunk?
Registration or IP-authenticated trunk credentials, the codecs to allow, the DIDs to route inbound and the caller ID to present outbound, plus firewall rules for SIP signalling and RTP media. The settings are confirmed with your administrator during planning and tested on a temporary number before your production numbers move to the trunk.
Learn more
- SIP trunkAn internet connection between your own PBX and the public phone network, replacing physical lines.
- Cloud PBX vs traditional PBXOwn the switch or rent it: ownership, maintenance, remote users and the path between them.
- SIP trunkingCanadian numbers and call paths for the PBX you already run.
- Hosted PBXThe PBX as a service: endpoints, extensions, dial plans, failover and admin.
- 9-1-1 on VoIPWhy the registered address matters, how it is confirmed at setup, and how to keep it current.
Learn more
Works with the tools you already use.
Integrations are scoped during planning based on your systems; availability is confirmed before activation.
- Webhooks & APICustom
Related products.
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SIP calling that replaces landlines — or feeds the PBX you already own.
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Local, toll-free and campaign numbers that all land in one system.
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Reliable calling with routing your team will actually use.
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Queues, routing and supervision for teams that live on the phone.
Learn more: Contact CentreAcross Canada
SIP trunking by city and province
Frequently asked questions.
A SIP trunk is a connection over the internet between your PBX and the public phone network. It replaces the copper lines or PRI circuit your PBX used to plug into. Calls travel as data to 3CTel, which hands them to the carriers, and inbound calls to your numbers arrive the same way.
A channel is the capacity for one call at a time. A DID is a phone number. You can have many numbers and few channels, or the reverse. Channels are quoted on how many calls you run at once; DIDs are quoted per number.
Any system that supports standard SIP trunking: 3CX, FreePBX and Asterisk-based systems, most on-premise IP PBX platforms, and older PBX systems connected through a SIP gateway. We confirm the specific settings with your administrator during planning.
Canadian VoIP providers must provide 9-1-1 service and warn customers of its limitations. The registered service address for each site is confirmed with you at setup, and you are responsible for telling us when a location changes so the address stays current.
The trunk detects that the PBX is unreachable and forwards inbound calls to the target you chose for each DID — a cell phone, another site or voicemail. Outbound calls resume when the PBX registers again.
Per channel plus usage, quoted after we review your peak concurrent calls, the numbers you need and where you call. DIDs and toll-free numbers are itemised separately. Nothing is billed before activation.
Get a SIP trunk quote sized to your PBX.
Tell us the PBX you run, your busiest hour and the numbers you want to keep. A specialist will scope channels, DIDs and failover and send a quote.