Callio, the most affordable and efficient telephone system available for prisoners and others to contact you on anywhere in Australia. For as low as $4.35 per week, you can receive unlimited calls from anyone, including inmates, Australia wide. Unlike other services that provide customers with a local land line number which diverts calls to a users mobile phone, Callio is not a diversion based telephone system. Instead, Callio allocates users with their own personal land line number that is operated directly from the Callio app installed on their phone. Inmates and others then call that local land line number to enjoy the benefits of a local call rates as opposed to significantly higher mobile phone rates which are charged per minute."here is no way to get around the official prison phone providers, but you can save a lot of money if your inmate calls a local number instead of mobile number. There is no way to get around the official prison phone providers, but you can save a lot of money if your inmate calls a local number instead of long distance. Callio provides you with a number local to the facility where your loved one is located, connected with your cell phone.