What is Extension number?

An extension is a short internal number — usually two to four digits — that reaches one person or one phone inside a business, without going through the public phone network.

Dial 204 and the warehouse manager answers. Because internal calls never touch the phone network they are free and they behave the same wherever the person is sitting, so a team spread across several countries still works like one office. "Three extensions" means three people can be signed in, each with their own number, login and softphone. Silux Call includes internal extensions from Growth, or £2/month as an add-on.

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