How to convert analog communication to voip?

Question

SIP

Colleagues, good afternoon.
I'm starting to engage in telephony, sorry for the profane questions.
Please tell me how you can convert analog telephony to voip, it’s clear about setting up asterisk, the process of converting a number to a number is not clear. That is, a wire came with a city number, then where is it?

Answer 1

To the FXO Gateway . This can be a separate device that is immediately connected to the network via SIP, or a PCI board that is plugged into a system unit with an asterisk (it understands such boards).
If there are IP phones in the office, getting a phone from the provider by wire is an anachronism. Most providers make it possible to receive telephony immediately in VOIP format over the Internet or a leased line.

Answer 2

You can make a request to the operator, some operators can give your telephone line in digital (SIP) via the Internet and such a line can be multichannel.
The simplest option is the FXO gateway, but the line will remain single-channel.