At the board a player may have an electronic device (such as a mobile phone, tablet, smart watch, etc.) that can receive and/or transmit data only if the device is off (not just in airplane mode) and not in sight. The device must be out of sight and in something else (such as a jacket pocket, a pants pocket, a backpack, etc.).
At the board a player may not have in or around the player’s ear a device (such as headphones, earbuds, etc.) that can receive and/or transmit data—unless it’s a medically approved hearing aide. A player may have in or around the player’s ear a device (such as earplugs) to block out sound; however, earmuffs are forbidden, because it would be too difficult to determine whether they’ve been electronically modified.
At the board a player may use a personal electronic recording device only if it is US-Chess approved. US Chess has approved only the following personal electronic recording devices that generate electronic scoresheets (escoresheets) [source: US Chess’s Approved Electronic Scoresheets [2014.01.01]]: