The sixty-second answer
Yes. A published number is an address, not a handset, and it can reach as many people as you want. Pick one of three patterns: ring everyone at once, ring in order, or one person answers and transfers. Then decide what happens when they are all busy.
Why the answer is yes
The idea that a phone number belongs to one telephone is a hangover from copper wiring, where the number really was the pair of wires. On a modern system the published number is an address that gets looked up when a call arrives, and the lookup returns whichever devices are currently signed in as that person or team [2].
That single change is what makes everything in this article possible. One person is not limited to registering from a single device, more than one user can be signed in on the same device, and a call can be offered to several destinations at once in what the standards call a parallel search [1]. Translated: your number can ring a desk phone, a laptop, and two mobiles simultaneously, and none of that requires a second line on the wall.
If the underlying idea of an extension is unfamiliar, start with what is a phone extension.
Pattern one: ring everyone at once
Every phone rings, the first person to pick up gets the call, everyone else's phone goes quiet.
This is the right default for two to about six people who all do broadly the same work: a clinic front desk, two partners in a trade, a shop with a counter and a back office. It is simple, it needs almost no maintenance, and it converts the classic "we were both with someone" miss into an answered call more often than any other single change.
Its weakness is noise. If one of the two people is doing focused work, or is with a client, a phone that rings for every call becomes something they learn to ignore, which quietly turns your setup back into pattern two without anybody deciding.
Pattern two: ring in order
One person gets the first chance for a set number of rings. If they do not answer, the call moves on to the second person, then the third, then to a message.
Use this when the people are not interchangeable. The obvious case is an owner whose time is expensive and an assistant who should get first crack at routine calls; the reverse is also common, where a specialist gets first refusal and everyone else catches overflow. Keep each stage short. Callers do not experience the elegance of your escalation ladder, they experience ringing, and most people give up somewhere between fifteen and thirty seconds.
The stage everybody forgets is the last one. A ladder with nothing at the bottom drops the caller into a dead end, which is one of the ways callers end up hearing a busy signal instead of a message.
Pattern three: one answers, then transfers
The traditional model, and still the right one when the caller usually needs to reach a specific person. One person answers everything, finds out who is needed, and passes the call on.
It stands or falls on the transfer being genuinely quick and on the receiving person being reachable at all, which is much easier when their extension also rings their mobile. If the two people are in different buildings, the mechanics are in transferring calls between two locations, and for a mixed office and remote team in one dial plan across sites and remote workers.
How to choose between the three
Answer two questions. Do the two people do the same kind of work, and does a caller usually ask for a person by name? If the work is the same and callers do not ask for anybody in particular, ring everyone at once. If the work is the same but one person's time is worth protecting, ring in order. If callers routinely ask for a named person, have one person answer and transfer.
You are allowed to change your mind. These are settings, not construction, and it is normal to run one pattern for a month, find it noisy or slow, and switch. What is not normal is running whatever the previous installer left behind for six years because nobody knew it was a choice.
The four things that break
Nobody owns the miss. When two phones ring and neither person answers, both assume the other took it. Assign the follow-up to a person by name for each mailbox, or the message sits. The rule that works in practice is that the person who is rostered on the counter that day owns every message left that day, whether or not their phone was the one that rang.
The bottom of the ladder is empty. Decide today what a caller hears when both of you are on calls. Standards assume a busy destination is routed onward rather than refused [2]; your configuration has to actually say where.
Outbound calls give the game away. If either person rings a customer back and their personal mobile number appears, the customer now has it forever, and your shared number stops being the business's identity. Outbound calls from a business extension should present the business number regardless of the device used.
Shared voicemail becomes nobody's voicemail. It also becomes a privacy question, because messages contain customer information collected for a stated purpose. PIPEDA's Schedule 1 requires knowledge and consent for collection and use, limits use to the purpose for which the information was collected, and asks for documented procedures governing destruction of what is no longer needed [3]. Practically: decide who can listen, and decide when old messages go.
What about capacity?
Sharing a number does not by itself let you take more calls at the same time. Those are two different settings, and confusing them is a common and expensive mistake: a business adds three people to the number, then discovers the fourth caller still gets refused because the limit on simultaneous calls never moved. Work out the number you need in how many phone lines does my business need, then check how your provider counts people in how to count extensions and choose a band.
What it should cost you to add a person
Adding a second person to a number is a configuration change, so be suspicious of anything that treats it as a project. What varies legitimately is how you are billed for the person: per seat, or by a band that covers a range of extensions. The two models are compared in per-seat versus flat-band pricing.
Whichever model you are quoted, ask for the all-in monthly figure with every mandatory charge included, in writing. Subsection 74.01(1.3) of the Competition Act treats a price that is not attainable because of fixed obligatory charges or fees as a false or misleading representation, unless the charge is imposed under an Act of Parliament or of a provincial legislature [4]. Getting the answer in an email costs nothing and settles the argument in month three. If the bill has already started drifting, see why does my business phone bill keep changing.
Where we sit
We run hosted phone systems for Canadian businesses, and shared numbers are ordinary work rather than a premium tier: your published number can ring any combination of desk phones, computers and mobiles, in parallel or in sequence, with a named destination at the bottom of the ladder. Adding a person is a change, not a rebuild.
We will also say when you do not need it. A business where one person genuinely answers everything is better served by a simple setup and a good after-hours path, which is covered in whether a one-person business needs a phone system. Reliable telephone service is treated in Canadian law as infrastructure rather than a luxury, with section 7 of the Telecommunications Act affirming its essential role and setting out the objective of an orderly system throughout Canada [5]; the 1.08 million small businesses here [6] should not have to buy a call centre to let two people answer one phone. What is included, and how extensions are counted, is on our pricing page.