How to connect a VoIP phone to an analog PBX?

Question

VoIP

There are automatic telephone exchanges with free analog internal lines. There are VoIP phones. Is it possible somehow (through a gateway?) to connect VoIP phones to analog extensions?
Googling so far gives only the reverse option: analog phone -> VoIP server. There are no problems with this.
Thank you!

Answer 1

You need approximately this device.
Register an IP phone on the gateway, give a number, set up transfer from the fxo port to the sip number that was assigned to the ip phone. Outgoing send to fxo - in fact everything.

Answer 2

you need a gateway with
FXO not all IP-phones can work without registration