How to switch business phone providers and keep your numbers

What the rules say

Moving a number from one provider to another is called porting. FCC rules require phone companies to port numbers, and internet phone (VoIP) providers have to cooperate with ports in and out as well. A VoIP provider can't sign you up under an agreement that stops you from taking your number elsewhere.

A simple port, generally a single line, has to be completed within one business day once the old provider has an accurate request. Other ports, which covers most business accounts with several lines, have four business days. Either can take longer if you or the new provider ask for a later date.

For a simple port, the old provider can only require a short list of details, including the phone number, the account number, the ZIP code, and a passcode if one was set on the account.

Sources: 47 CFR 52.34, 52.35 and 52.36.

What to gather before you switch

• A recent bill from the current provider, with the account number and the billing name and address exactly as they appear.
• The account passcode or PIN, if there is one. Mobile accounts usually have a separate port-out PIN.
• A list of every number on the account, not just the main one. Bills often show a main number and hide the rest.
• What each number does: main line, direct lines, fax, alarm panel, elevator phone, credit card terminal, a line for DSL internet.
• Any toll-free numbers. They move too, through a separate process, so list them on their own.
• Who is allowed to sign for the account. The new provider needs a signed letter of authorization from that person.

The order to do things in

• Set up the new phone system first, with its menus, users and phones working on temporary numbers.
• Submit the port with the details from the bill. Pick a date and time when a short gap won't hurt, like early in a weekday morning.
• Leave the old service alone. Don't cancel it. When the port completes, the number moves and the old account stops billing for it.
• On port day, call each moved number from a cell phone and check where it rings. Then check outbound calls show the right caller ID.
• Set the emergency (911) address for every phone on the new system.
• Only after everything works, cancel whatever is left on the old account, like lines you didn't move.

Cancelling first is the expensive mistake. Once an account is closed, the number can be released, and getting it back is not guaranteed.

What usually breaks

• Fax. Fax machines don't always work well over internet phone lines. Plan to move fax to online fax, or keep it on a separate line replacement.
• Alarm panels, elevator phones and gate call boxes. These dial out over a phone line and usually shouldn't move to the new phone system at all. They need a line replacement instead. See what a POTS line is and what replaces it.
• DSL internet. If your internet is DSL from the same phone company, it may run on one of the lines you're moving. Moving or cancelling that line can take the internet with it. Ask before you port it.
• Hunt groups and rollover lines. Numbers that only exist to roll calls to the next line often don't need to move. Rebuild the call flow on the new system instead.
• Directory listings and caller ID name. Check the business name that shows on outgoing calls after the move, and update it if it's wrong.