Channels
A channel is one concurrent call, inbound or outbound. You choose how many the trunk carries, and the count is adjusted as your call volume changes rather than fixed by the number of physical lines.
For businesses keeping their PBX
Keep the PBX. Replace the phone lines.
You have a 3CX, FreePBX or on-premise system that works, and a set of phone lines or an old trunk contract that does not. SIP trunking connects your PBX to the Canadian phone network over the internet, with your numbers, your caller ID and a failover plan.
- Works with 3CX, FreePBX, Asterisk-based and other IP PBXs
- Canadian local and toll-free DIDs, ported or new
- Failover to another destination when the PBX is unreachable
Example
Site A
Site B
Mobile
Your PBX or apps
3CTel SIP trunks
Call quality: HD
Carrier network
SIP trunking connects a PBX you own, such as 3CX, FreePBX or another IP PBX, to the public telephone network over the internet. 3CTel provides the trunk, the concurrent call channels, Canadian local and toll-free numbers, porting of your existing numbers and caller ID presentation. If your PBX or internet link becomes unreachable, inbound calls can be routed to a fallback destination automatically.
Who keeps their PBX, and why
Not every business wants a hosted service. Some have a recent PBX investment, custom integrations, an administrator who knows the system, or a policy that keeps call control on site. Others run 3CX or FreePBX because they like the control. For all of them, the part worth replacing is the connection to the phone network: the analogue lines, the PRI or the trunk provider whose contract has become expensive or inflexible.
A SIP trunk from 3CTel replaces that connection. The PBX keeps doing the routing; 3CTel provides the numbers and the call paths.
SIP Trunking
Carrier-grade SIP trunks for the PBX you already run — channels, DIDs and failover sized to your traffic.
Learn more: SIP TrunkingSIP trunk
An internet connection between your own PBX and the public phone network, replacing physical lines.
Learn more: SIP trunkHosted PBX
The PBX as a service: endpoints, extensions, dial plans, failover and admin.
Learn more: Hosted PBXChannels, DIDs and numbers
DIDs
Each public number is a DID delivered over the trunk with the dialled number attached, so the PBX routes it to the right extension, menu or queue. Add as many as you need across cities.
Canadian local numbers
Numbers in the area codes you serve. A business in one city can present a local number in another for a regional sales line.
Toll-free
Toll-free numbers terminate on the same trunk and are routed by the PBX like any other DID.
Porting
Existing numbers are ported to the trunk. The old lines keep working until the port completes, and the switch date is agreed with you.
Usage visibility
Call detail records are available for reconciliation against your PBX's own logs.
Business Phone Numbers
Local, toll-free and campaign numbers that all land in one system.
Learn more: Business Phone NumbersDID (Direct Inward Dialing)
A phone number that reaches a particular extension or department directly, bypassing the main menu.
Learn more: DID (Direct Inward Dialing)Number porting
How a port works, what you need to provide, what causes delays, and what 3CTel does at each step.
Learn more: Number portingCaller ID and outbound presentation
Outbound caller ID is set by the PBX per extension or per trunk and must be a number on your account. That lets you present the main number for most users, a direct-dial number for account managers and a regional number for a local sales line.
- Name display: the caller name shown to recipients is set on the numbers with 3CTel, since the name is delivered by the receiving carrier's database rather than by the PBX.
- Per-DID presentation: a call returned from a shared team can show the number the customer originally dialled.
- Restrictions: the PBX controls which extensions may dial international or premium destinations; the trunk can be limited as a second safeguard.
- Emergency calls: each site and, where relevant, each extension is associated with a registered service address confirmed with you at setup. Canadian VoIP providers must provide 9-1-1 service and warn customers of its limitations.
Failover when the PBX or the link is down
Some organizations pair the trunk with a small set of hosted extensions on 3CTel for key staff, giving them a working phone even when the PBX is offline.
Detect
If the PBX stops registering or stops answering calls on the trunk, 3CTel treats the destination as unreachable.
Reroute
Inbound calls to each DID follow a fallback you defined in advance: a cell phone, another site, a hosted voicemail or a hosted menu on 3CTel.
Restore
When the PBX registers again, calls return to it automatically. No ticket is needed to switch back.
Review
Call records show what was rerouted and where, so you can confirm nothing was missed.
Connecting common PBX platforms
| PBX | How it connects | Notes |
|---|---|---|
| 3CX | SIP trunk configured in the 3CX admin console | Inbound DIDs mapped to 3CX rules; outbound caller ID per extension |
| FreePBX / Asterisk-based | SIP trunk with registration or IP authentication | Inbound routes per DID; outbound routes with caller ID overrides |
| Other IP PBX | Standard SIP trunk configuration | The specialist confirms settings against the vendor's documentation |
| Legacy PBX with PRI or analogue lines | SIP-to-PRI or SIP-to-analogue gateway | Keeps an older system running on modern trunks until it is replaced |
SIP Trunking
Carrier-grade SIP trunks for the PBX you already run — channels, DIDs and failover sized to your traffic.
Learn more: SIP TrunkingPBX (Private Branch Exchange)
The private switch that connects a company's extensions to each other and to the outside world.
Learn more: PBX (Private Branch Exchange)Questions from PBX administrators
How many channels do we need?
Count the most calls you expect at the same time, inbound and outbound together, and add some headroom. Your existing line count or PRI capacity is a starting point, and call records from the current system show your real peak. Channels are adjusted as needs change, so the aim is a sensible starting number rather than a permanent decision.
Can we test the trunk before porting our numbers?
Yes. A trunk is turned up with a temporary DID so you can verify registration, inbound routing, outbound caller ID and audio in both directions from your PBX. Once you are satisfied, your existing numbers are ported onto the trunk, and the temporary number can be kept or released.
Can we move to a hosted service later without changing numbers?
Yes. The numbers belong to your account, not to the trunk. If you retire the PBX, the same numbers are pointed at hosted extensions on 3CTel and users move across. Many businesses do this gradually, running the trunk and hosted extensions side by side while one site or department at a time migrates.
Related pages.
SIP Trunking
Carrier-grade SIP trunks for the PBX you already run — channels, DIDs and failover sized to your traffic.
Learn more: SIP TrunkingHosted PBX
The PBX as a service: endpoints, extensions, dial plans, failover and admin.
Learn more: Hosted PBXBusiness Phone Numbers
Local, toll-free and campaign numbers that all land in one system.
Learn more: Business Phone NumbersSIP trunk
An internet connection between your own PBX and the public phone network, replacing physical lines.
Learn more: SIP trunkEnterprise
Contact centre and back office on one platform, migrated in stages.
Learn more: EnterpriseNumber porting
How a port works, what you need to provide, what causes delays, and what 3CTel does at each step.
Learn more: Number portingFrequently asked questions.
Both are supported. Registration is common where the PBX has a dynamic address; IP authentication suits a PBX with a fixed public address. The specialist confirms which fits your setup.
The standard codecs used by mainstream PBXs are supported. The specialist confirms the codec settings with your administrator during turn-up so audio matches your PBX's configuration.
Alarm and elevator lines often have specific requirements. Discuss them with the specialist; some can move to an adapter, others are better left with their current provider.
Channels are quoted for your expected volume. Ask the specialist for the minimum and how changes are handled during your term.
Pricing is quoted for your channel count, numbers and calling needs before activation. Nothing is billed before the trunk is live.
Tell us what PBX you run.
Send the platform, your channel estimate and the numbers you want to keep. A specialist confirms the configuration and quotes the trunk.