Final answer:
The use of cell phones for voice communications is prohibited unless certain conditions are met, such as maintaining a quiet environment or avoiding interference with important equipment.
Step-by-step explanation:
The use of a cellular phone or other handheld wireless communications device to engage in voice communications is prohibited unless certain conditions are met. For example, in many public places, such as classrooms or libraries, the use of cell phones for voice calls may be prohibited in order to maintain a quiet and focused environment. Additionally, in certain situations where the use of cell phones may interfere with important communications or medical equipment, their use may be prohibited.