Phone number without geographic restriction based on VoIP. The number can be masked as a national telephone number within a flat rate contract and may be exempt of costs to both the caller and the receiver of the call. With regards to over-the-phone interpreters, these numbers allow the customer to be offered a service at the cost of a national call although the interpreter is physically present in another country.
Prefijo 51 España, el número nómada VoIP. https://serviciosonline.net/internet/voip/prefijo-51-espana-numero-nomada-voip/