Leaving a PBX or a Centrex line without breaking what works

Moving off an on-premise switch or a Centrex line happens in three stages: inventory what exists, build the new system alongside it, then move the numbers last. The most expensive mistake is doing the third one first.

First, a deadline that does not exist here

Almost every French-language guide on this subject is built around la fin du RTC. That is real, and it is French. It refers to the incumbent carrier switching off the public switched telephone network in France, with announced dates.

There is no Quebec equivalent on that timetable. If a vendor is pressing you with a network shutdown date, ask which one, and in which country. Your reason to migrate may be excellent; that is not it.

The inventory nobody does

A phone system that has been in place for fifteen years contains things nobody documented. Before touching anything, write down:

• Every number, and what it does. There will be more than you think: the main line, the fax, the old accounts-department line, a toll-free number nobody cancelled.
• The forwards, especially any that end on someone's personal mobile. That is where the day-after surprises hide.
• The hunt groups: which number overflows to which, and in what order.
• The things that are not phones. Payment terminal, alarm panel, elevator, front door. These use an analogue line and do not migrate like an extension.

That last point is what sinks migrations. An elevator on an analogue line is not a desk phone: it is a safety device with its own rules, and it is handled separately, with whoever maintains it.

The order that protects your numbers

1. Build the new system alongside the old one. Temporary numbers, call flows built, staff trained, while the old system keeps running.
2. Test with real calls, not just the greeting: a transfer, a queue overflow, a voicemail, an after-hours call.
3. Move the numbers last, and cancel nothing until the port completes. A cancelled number returns to the pool and is not always recoverable: detail here.

You will pay two providers for a few days. That is the cost of not losing a number your customers have dialled for ten years.

The moment to take advantage of

A migration is the one occasion when everyone agrees to revisit routing. The seven-option menu inherited from 2011 does not have to be rebuilt exactly as it was.

It is also the right moment to check two specifically Quebec things: that the greeting satisfies the Charter, and that you know where your recordings end up. See Law 96 and where your call data lives.

What we do

We build the flow in advance, prepare the port with you, and cut nothing over until the numbers have arrived. There is no self-serve migration in the product: this is something we run with you.