Refrigeration monitor system with remote signalling of alarm indications

A refrigeration monitor system for monitoring a freezer or compartments containing perishable products and for automatically transmitting freezer failure alarms, the system comprising:

• at least one freezer group comprising a plurality of freezer compartments, each compartment containing at least one thermal sensor having an adjustable upper temperature setting;
• at least one telephone line connectable through switching means to at least one remote telephone instrument of the DTMF type having a callable telephone number;
• number storage means for storing at least one callable telephone number in machine memory, said number storage means communicating with line control means capable of connecting said number storage means to said telephone line and dialling said callable telephone instrument;
• recorded message means for recording and on demand playing recorded messages said recorded message means communicating with said line control means for playing into said telephone line recorded messages;
• tone receiver of the DTMF type for receiving tone-encoded signals and codes, communicating with said line control means for receiving signals for start of dialling and receiving manually produced answer codes of the DTMF type from said telephone instrument;
• control means responsive to said temperature sensor such that upon attaining said upper temperature setting, said temperature sensor operatively activates said control means to traverse a control program stored in memory, said control program comprising a sequence of steps causing said callable telephone instrument to be dialled by said stored telephone number and to be connected to said recorded message means and to be connected to said DTMF tone receiver means for detection of a manually produced preselected answer code from said DTMF telephone insutrument, said answer code operating to cause said line control to disconnect from said telephone line;
• communications means linking said freezer group with said line control having
• a first radio receiver-transmitter combination in wired two-way communication with said line control means;
• a second radio receiver-transmitter combination in wired two-way communication with said thermal sensors;
• said first radio receiver-transmitter combination transmitting on a first frequency and receiving on a second frequency;
• said second radio receiver-transmitter combination transmitting on said second frequency and receiving on said first frequency;
• said first and second radio receiver-transmitter combinations in mutual wireless two-way communications.