As someone with very little telco knowledge, could you use something like this as a voip gateway for a legacy pbx ? Would it be as simple as writing some high

As someone with very little telco knowledge, could you use something like this as a voip gateway for a legacy pbx ? Would it be as simple as writing some high level software that interfaces with readily available libraries or would more possibly be necessary? I’m fascinated by the opportunity that all of the legacy circuit switched(pardon me and my naïve googling if that’s the wrong term) hardware has left in critical places.