Keeping your fax number when you move providers
In most cases you can take the number with you. It is a portability request, it takes days rather than minutes, and the one thing that kills it is cancelling the old line first.
The number is usually the reason people stay somewhere they have outgrown. It is on the letterhead, in a hundred other organisations' address books, and printed on forms nobody will reprint. The good news is that a fax number is portable in the same way a phone number is, and for the same reason: it belongs to the numbering plan, not to the provider.
The one rule that matters
Do not cancel the old service
A number that has been disconnected cannot be ported — it goes back into the pool, and in most countries there is no route to get a specific one back. Start the port, wait for it to complete, and cancel afterwards. This is the mistake that cannot be undone.
What a port actually involves
- A letter of authorisation. You are telling the losing provider that the gaining one may take the number. It has to be signed by whoever the account is actually in the name of, which is often not the person doing the work.
- A recent bill from the losing provider, as proof of who holds the number. The details on it — the account name, the service address — have to match what you put on the authorisation, exactly. A mismatch is the most common reason a port is rejected.
- A date. Ports complete on a scheduled date rather than on request. Business hours, on a working day.
- A short window where both ends exist. The number stops answering at the old provider and starts answering at the new one; the switch is quick but it is not instantaneous.
How long it takes
Days to a few weeks, depending on the country and on how quickly the losing provider responds. Ports within the same country are routine; a number is never portable to a different country. The delay is almost never technical — it is the losing provider's process, and they are not in a hurry.
When you cannot port
- The number is part of a bundle the provider will not break up — common where a fax number was issued alongside a voice line.
- The account is in a name that no longer exists, after a merger or a rebrand. Fixable, but it is paperwork before it is a port.
- There is a contract term left. You can usually still port, and still owe the remainder.
- The line is already disconnected. Nothing to be done — see the warning above.
The alternative, when the port is not worth it
Take a new number and forward the old one for as long as the old provider will let you. It costs the old line for a while, and it buys the time to change the letterhead, tell the people who fax you most, and let the rest arrive by forwarding. Six months of overlap is usually more than enough.
If you are moving because the line itself is going away, the timing is tighter — the port has to happen before the line is retired. Faxing without a phone line covers why that deadline exists.