When the school bell rings, phones are put on silent. The Tucson Unified School District is adopting a new cellphone policy. The move comes after Arizona Gov. Katie Hobbs signed a bill last month requiring schools to limit phones during class time. The new policy is called a “bell-to-bell” policy and was adopted unanimously by the TUSD Governing Board on Tuesday night. It also receives support from Stand for Children Arizona, a state-wide organization.