If a device does not recognize the SIM card, what should you check first?

The most effective initial step when a device does not recognize the SIM card is to inspect the antenna and cables. This is because a poor connection or physical issues with the antenna or cables can lead to problems with the device's ability to detect the SIM card. If the antenna is not properly connected, or if there is damage to the cables, it can hinder communication between the SIM card and the device. Checking these hardware components first allows for the identification of any physical issues that might be causing the connectivity problem.

While checking phone settings for network access, resetting network settings, or power cycling the device can all be useful troubleshooting steps, they are generally more appropriate once hardware aspects are confirmed to be in good working order. If the physical aspects are functioning correctly, these additional steps would then be relevant to further isolate the issue.