You can ban cellphones in the classroom. Students caught with a cellphone can have it taken away and placed in your desk. However, some students may try to sneak cellphones into the classroom. This forces you to regularly check to see whether students have cellphones. Checking students' bags for cellphones can not only waste time but also violate student privacy. Some parents may be offended by cellphone bans. Also, some students keep cellphones only for emergencies and use them responsibly.
You can allow cellphones, but only if students do not use them in the class. You can require that students turn them off before class starts. When a student is caught using a cellphone in class or when the phone rings, you can temporarily or permanently ban that student from bringing cellphones. You will have to monitor the class to make sure no students use their cellphones, since they can sometimes mute the cellphone but leave the phone on, allowing them to send text messages covertly.
You can allow students to bring cellphones into the classroom and place the phones in a tray before the class begins. Before leaving, the students can collect their phones. However, this can create confusion when two students have similar cellphones. Also, students may try to steal cellphones that do not belong to them. When caught, the student can say that he confused the stolen phone with his own phone. You can use sectioned trays so each student can put his phone in an individual section, minimizing confusion.
If you are concerned only with students cheating on tests but can tolerate text messaging, have students put cellphones in a tray only during the test. Then, when they complete the test, they can return to the tray and grab their phones. This creates less confusion, since the students won’t come to the tray simultaneously, since they will all finish their tests at different times.