Should You Leave the SIM Card in an Old Phone Security Camera? A Dual-SIM Guide for Offline, Wi-Fi and Mobile Data Setups
Most old Android phones that become security cameras still have a SIM card inside. Often it is the old number from before the upgrade. Sometimes it is a cheap prepaid SIM that came with the phone. On a dual-SIM handset there may be two. Nobody decides to leave them there. They are just there. And those SIM slots change how the camera behaves: whether it spends money on data, whether it comes back after a power cut, and whether your bank's one-time passwords show up on a phone sitting on a shop…