Cellular modem for low power applications

A metering device, comprising:

• one or more power supplies, configured to provide power at a first power level and a second power level;
• a metrology unit, powered by the one or more power supplies;
• and
• a cellular module, powered by the one or more power supplies, wherein the cellular module comprises:
• a radio, configured to transmit data when powered at the second power level;
• a processor, to control the radio;
• a memory in communication with the processor;
• and
• a general-purpose input/output (GPIO) pin, controlled by the processor, to signal the one or more power supplies to transition between the first power level and the second power level, wherein the second power level is higher than the first power level;
• wherein the cellular module performs actions comprising:
• receiving, at the processor and from the radio, an appointed time for a next communication;
• determining a time to activate the second power level of the one or more power supplies, to power the radio at the appointed time for the next communication;
• and
• sending a signal from the GPIO pin at the determined time.

A method of operating a cellular module, comprising:

• signaling one or more power supplies to transition between a first power level and a second power level, wherein the second power level is higher than the first power level, and wherein the signaling is performed by voltage on a general-purpose input/output (GPIO) pin of the cellular module;
• receiving, at a processor of the cellular module and from a radio of the cellular module, an appointed time for a next communication;
• determining a time to activate the second power level of the one or more power supplies, to power the radio to be ready for the next communication at the appointed time;
• and
• sending a signal from the GPIO pin at the determined time.