The 60-second answer
Bring your own trunk (BYOT) hosted PBX means you buy the call-control software from one provider and keep buying the phone lines from your existing carrier. Your numbers, your contract and usually your handsets stay exactly where they are. Only the brain of the phone system is replaced.
The distinction nobody explains at the sales stage
A business phone system is not one product. It is two, and they are sold by different kinds of company for different reasons.
The first is transmission — the physical or logical path that carries a call between your building and the rest of the world. Canadian law is unusually precise about who that is. The Telecommunications Act defines a telecommunications common carrier as “a person who owns or operates a transmission facility used by that person or another person to provide telecommunications services to the public for compensation” [1]. Owning or operating the facility is the test. That is your carrier.
The second is call control — the logic that decides what happens after a call arrives. Which extension rings. Whether it rings three phones at once or one after another. What the auto-attendant says at 4:55pm on a Friday versus 5:05pm. Where the voicemail goes. None of that involves owning a transmission facility, and the same statute treats a “telecommunications service” as a distinct thing from the facilities it runs over [1].
The industry blurs these together because bundling is profitable. A carrier that sells you both can price the PBX as a loss leader, bury it in a three-year term, and make the margin back on per-minute rates and line charges you never re-negotiate. Nothing about the technology requires that bundle. The two halves speak a published, open protocol to each other, and have since 2002 [2].
What BYOT actually changes
| Component | Before | After BYOT |
|---|---|---|
| Phone numbers / DIDs | Your carrier | Your carrier — unchanged |
| Trunk / lines / dial tone | Your carrier | Your carrier — unchanged |
| Long distance rates | Your carrier contract | Your carrier contract — unchanged |
| Caller ID authentication | Originating carrier | Originating carrier — unchanged [4] |
| Call routing, extensions, IVR | Old PBX or carrier portal | MapleReceptionist |
| Voicemail | Old PBX or carrier | MapleReceptionist, delivered to email |
| Desk handsets | Yours | Yours — re-registered, not replaced |
| Monthly cost of the PBX | Bundled, often invisible | A flat, published number |
Read that table twice, because it is the entire argument. Seven of the eight rows do not move. The disruption of switching a phone system is almost entirely concentrated in the rows a BYOT migration never touches: porting numbers, renegotiating rates, replacing hardware, retraining staff on a new dial plan.
Why this is technically possible
Session Initiation Protocol splits a call into two independent streams. The signalling — ring, answer, transfer, hang up — is SIP, standardised as RFC 3261 [2]. The audio itself is a separate real-time stream, standardised as RFC 3550 [3]. Because signalling and media are decoupled, and because SIP is a registration-based protocol where a device authenticates to a server with an address, a username and a password, any conforming handset can register to any conforming PBX [2].
That is the whole trick. A desk phone does not know or care who bills you. It knows a server address, an extension, and a secret. Change those three fields and the phone is on a different PBX, still using the same trunk, still ringing on the same number.
One thing that does not move is caller identity attestation. The signature framework that lets a receiving network judge whether a calling number is legitimate is applied by the originating carrier as part of the signalling path [4]. Because your carrier is still your carrier, your outbound calls keep whatever attestation level they had. Changing your PBX does not degrade your caller ID reputation — a genuine risk when you port numbers to a new carrier and start again from a cold reputation.
The money, stated plainly
Market pricing for business phone service in Canada falls into two bands that are frequently compared as if they were the same product:
- $20 to $35 per seat per month — full-service hosted voice. The provider sells you the PBX and the lines and the numbers, and carries the per-minute cost.
- $8 to $15 per seat per month — PBX-only service, where you bring the trunk. Less service, and correspondingly less money.
MapleReceptionist prices the second category, but not per seat. Pricing is banded, in Canadian dollars, with HST added at checkout according to your province:
| Extensions | Monthly (CAD + HST) | Effective per extension | Setup |
|---|---|---|---|
| Up to 10 | $99 | $9.90 | $350, or $250 with a 12-month commitment |
| Up to 25 | $219 | $8.76 | $750 |
| Up to 50 | $399 | $7.98 | $1,200 |
| Up to 100 | $699 | $6.99 | $1,900 |
Over 100 extensions is quoted individually. Bands are ceilings rather than allowances, which matters more than it sounds: an organisation that hires four people in March does not receive a different invoice in March. It moves to the next band at renewal, on notice, with the number known in advance.
Per-seat pricing makes your phone bill a function of your headcount, which is the one number a growing business least wants coupled to a recurring cost. Banded pricing decouples them for the length of a term.
Capital versus operating cost
There is a tax dimension that on-premise vendors rarely raise. When you buy a phone system outright, you have bought depreciable property. The CRA places “electronic telephone equipment” in Class 8, written down at 20% declining balance [5]. A $12,000 system does not reduce this year's taxable income by $12,000; it reduces it by a fraction, and continues doing so for years, long after the equipment stops being the thing you would have chosen.
A hosted subscription is an operating expense in the year you incur it. For a small business managing cash rather than a balance sheet, that difference — full deduction now versus a declining-balance schedule — is often larger than the price gap between the two options in year one. It is worth putting to your accountant with real numbers rather than treating hosted-versus-owned as purely a technology decision.
What you get, and what you are still buying elsewhere
Included in every band: an extension for each person, Canadian-hosted voicemail with voicemail-to-email delivery, auto-attendant and IVR call-flow design, business-hours and after-hours routing, SIP trunk or analogue FXO integration, handset provisioning for the phones you already own, and roughly 30 to 60 minutes of administrative changes per month. Call records are handled under the ten fair information principles that govern personal information in Canadian commercial activity [6].
Not included, and deliberately so: phone numbers and DIDs, SMS and texting, and AI call handling. Those are separate products at separate prices. A hosted PBX that quietly bundles them is not cheaper; it is a bigger purchase wearing a smaller label.
Who this is actually for
The overwhelming majority of Canadian establishments employ fewer than 100 people [7], which is precisely the range these four bands cover. Within that range, BYOT hosted PBX is the right answer in a few recognisable situations:
- Your PBX is old, unsupported, or the person who configured it has left, but your carrier service is fine and reasonably priced.
- You are mid-term on a carrier contract and switching providers would trigger termination charges or break a bundled discount.
- You have serviceable handsets and no appetite for a hardware refresh you did not budget.
- You want the phone system's monthly cost to be one published number rather than a line item that moves with headcount.
It is the wrong answer if your carrier service itself is the problem — bad rates, poor call quality on the trunk, unresponsive support. In that case, fix the carrier first. A new PBX will faithfully route calls over a bad trunk.
Bottom line
“Bring your own trunk” is a narrow, honest description of a narrow, honest product: the call-control half of a phone system, priced separately, replaceable on its own. Canadian telecommunications law already draws the line between owning transmission facilities and providing a service over them [1], and the SIP standards have made the two halves independently swappable for over two decades [2]. The bundle was always a commercial arrangement, not a technical necessity. Unbundling it costs $99 CAD a month at the entry band, and leaves your numbers, your carrier and your handsets alone.