You'd just need a "certificate authority" system like we have with domains. Companies that wish to use a "virtual" phone number register as such with the provider (they probably already do), and the provider keeps a whitelist of those, which is enforced crytographically. Email had the same problem before MX records.
Maybe the challenge is doing all this in such a way that's compatible with legacy systems, though I'd think all of the complexity would live on the business exchange servers and the network itself, so "dumb" phones shouldn't have to know the difference.
Either way, I've learned to never underestimate the laziness and capacity for anti-consumerism of telecom companies.
Maybe the challenge is doing all this in such a way that's compatible with legacy systems, though I'd think all of the complexity would live on the business exchange servers and the network itself, so "dumb" phones shouldn't have to know the difference.
Either way, I've learned to never underestimate the laziness and capacity for anti-consumerism of telecom companies.