a space - efficient cellular modem device for machine - to - machine communications that includes : a multi - layer printed circuit board defining a top side and a bottom side and including a first circuit layer adjacent the top side , a second circuit layer adjacent the bottom side , a ground plane layer , and a power plane layer , the ground and power plane layers located between the first and second circuit layers ; a cellular transceiver module configured to communicate over a cellular wireless cellular network ; electrical power - management components attached to the multi - layer printed circuit board , the power - management components in electrical communication with the cellular transceiver module ; first and second rows of pins in electrical communication with the cellular transceiver ; and a communications port .