Elevator door control buttons are used to control the elevators' doors. In some modern elevator brands like Mitsubishi and Hitachi, the door open and close buttons will be lit when the button is held and unlit when unheld, and the door hold button will be lit when pressed and unlit when the door closes.
Most elevators have their door control buttons located below the floor buttons, but in some older Otis and Japanese elevators (like Hitachi, Toshiba, Fujitec, and Schindler Japan) are usually located above the floor buttons.
Door open button is on the left side while door close button is on the right side. Some elevators have this arrangement reversed.
Some modern Kone, Mitsubishi elevators and the elevators installed in America with two landing doors (front and rear) have two door control buttons on the control panel. These four buttons, two of them are used to operate the front doors while another two are used to operate the rear doors.
Door open button is used to re-open the doors when they are closing. It also function as holding the door open when it is kept pressed. However, pressing the door open button longer will cause the nudge buzzer to ring and the doors force close slowly. The door open button is normally identified as the symbol ◄ | ► , DO, simply Door Open or Open. Door open buttons are usually located on the left side next to door close button in most elevators. Few elevator brans have their own symbol variants. This is the only door control button is mandatory installed in the elevator.
Door close button is used to close the button immediately. Some European (like Express Lifts  and Schindler), older Dover, Mitsubishi  and Otis elevators and some modern elevators may not have a door close button, instead pressing a floor button will cause the door to close immediately (although door delay also exists). The door close button is normally identified as the symbol ► | ◄, DC, simply Door Close or Close. In some countries, the door close button is there for other services such as Firefighter's Operation or Independent Service, but is inoperable during normal usage. Door close buttons are usually located on the right side next to door open button in most elevators.
Door hold button is used to hold the door open for a desired period (normally three to five minutes) for loading goods, baggage, bed or stretcher. This button is especially common in freight and bed/hospital elevators. Door hold button is normally identified as Extend Open, Open Hold, DH or simply Door Hold or Hold. Sometimes, this service requires a keyswitch.