Moving your phone system to the cloud without an outage
Number porting is the part that goes wrong, and it goes wrong in predictable ways. Here is the sequence we use so the phones never stop ringing.
The TelcoCentric team2 min read
Almost every horror story about moving to a cloud phone system is really a story about number porting. The handsets arrive, the system is configured, everyone is trained — and then the numbers move at the wrong moment and the business spends a morning uncontactable.
It is avoidable. The trick is to stop treating the cutover as one event and start treating it as three, with the port last.
Build the new system while the old one still runs
The new platform does not need your numbers to exist. Stand it up in full — extensions, ring groups, hunt rules, voicemail, hold music, the lot — and give it a temporary number to test against. Everything you would discover on cutover day, you discover now, with no pressure and no customers waiting.
This is also when you find the things nobody documented: the after-hours diversion someone set up in 2019, the fax line the accountant still uses, the alarm dialler on an analogue port.
Make a real inventory
- Every number the business owns, including ones you think are disconnected
- Where each one currently terminates, and who answers it
- Analogue devices — EFTPOS, alarms, lift phones, fax
- After-hours and holiday diversions, and who can change them
- Any number printed on a vehicle, a sign or a contract
Run both systems in parallel
Point a handful of staff at the new system while everyone else stays on the old one. A week of real calls surfaces problems that no amount of testing will: the queue that rings too long, the extension nobody can remember, the headset that will not pair.
It costs a month of overlapping service. That is cheap compared with a bad first day.
Port the numbers last, and never on a Friday
A port is a scheduled change at the carrier. It normally completes inside a defined window, and if something is wrong, you want a full business day — and a carrier answering the phone — to fix it. Tuesday morning is the sweet spot. Friday afternoon is how you end up with a weekend of silence.
The single best predictor of a smooth cutover is whether someone made a complete list of numbers first.
Before the port completes, check the details on the porting form against the losing carrier’s records character for character. A mismatched account name or service address is the most common reason a port is rejected, and a rejection means starting the notice period again.
After the cutover
- Call every ported number from an outside line and confirm it lands where it should
- Test after-hours routing by temporarily forcing the out-of-hours rule
- Check outbound caller ID on every extension — it is often wrong for a day
- Leave the old system connected for a week before you cancel it
None of this is complicated. It is just a sequence, and the businesses that follow it do not have a story to tell afterwards.