In some cases, a phone that is left on, but not used, may incur charges. If a voice call is received but not answered, and the caller leaves a voicemail it is possible you will receive a charge for a voice call. If a text comes through and the phone is left on, you may be charged for a received text. Please note that smartphones (Blackberries, iPhones, Androids and other PDA devices) are constantly looking for data connections in order to perform updates and other synchronization steps. Therefore, it is possible that if you leave your PDA device on, you will incur data charges. Please contact your carrier for more information on data charges.