The invention discloses a digital program-controlled switch comprising a switch main body provided with a serial communication port circuit and a plurality of ordinary user port circuits, wherein the ordinary user port circuit is connected with an ordinary telephone set or an emergency telephone set; the emergency telephone set is used for outputting an emergency start signal and emergency notification content information; the serial communication port circuit is used for connecting serial data communication between a computer and the switch main body; the switch main body is used for outputting a ringing control signal when receiving the emergency start signal output by the computer/emergency telephone set, and sending the emergency notification content information output by the emergency telephone set to the ordinary telephone set when the hang up of the ordinary telephone set is identified; and the ordinary user port circuit is used for controlling the ordinary telephone set to ring when receiving the ringing control signal and sending the emergency start signal and the emergency notification content information output by the emergency telephone set to the switch main body. The digital program-controlled switch can realize one-key emergency call function, so that the operation is simple and convenient.