TD-1 is a programmable temperature detector, which can handle two independent sensors: built-in one and connectable external one. It monitors the temperature within the -35oC to +60oC range and alerts when it goes beyond the minimum or maximum threshold value. It can also provide information about exceedingly rapid temperature changes, which may be useful when indicating e.g. a sudden warming of air in the cold store. Connecting a bistable switch instead of the external probe makes possible toggling between two sets of critical parameters of the internal sensor, e.g. for day and for night. The detector enclosure contains three buttons for programming of the device, as well as a four-digit LCD screen, on which the current ambient temperature and the value read from the external probe are displayed. Error messages can also be displayed on the screen. The TD-1 detector has a built-in piezoelectric transducer for audible signaling, a tamper switch and two programmable relay outputs, which may be used for communication with the control panel or for control of another device.