Arnacon is a Web3 Telephony app that allows using regular GSM phone numbers as a Secondary Phone number, as well as web3 identities. It means you can either have a Secondary Number for Voice and SMS messages, or you can register with your e-mail address or ENS so people will be able to call your e-mail for Voice and sent you text messages.
You can verify your e-mail address or ENS to be used as your identity in the app - so other users can call your identity.
The solution is using a decentralised telephony network for MVNOs and service providers to connect their mobile systems and offer their services to the users.