A door/window magnetic sensing device comprising: a Hall effect sensor configured to sense signal strength of a magnet and output a signal strength value, the Hall effect sensor providing an output voltage when no magnetic field is sensed thereby, a controller for receiving the signal strength value from the Hall effect sensor, the controller configured to determine an alarm state, a normal state, and a tamper state from the signal strength value, a wireless transmitter circuit, wherein the controller is configured to control the wireless transmitter circuit to output a normal state wireless signal when the signal strength value is either above an alarm threshold value or below the alarm threshold value depending on an orientation of a magnet that is sensed thereby, a housing with a mounting plate for mounting in surface-to-surface contact with a door frame, a printed circuit board disposed within the housing and oriented transverse to the mounting plate, an indicator, wherein the Hall effect sensor, the controller, the indicator and the wireless transmitter circuit are provided with the printed circuit board and the Hall effect sensor is disposed on the printed circuit board away from the mounting plate, wherein the device is configured to, during installation, use the indicator to provide indication that a magnet assembly and the door/window magnetic sensing device are too far apart to perform door sensing; provide indication that the magnet is being detected by the Hall effect sensor of the door/window magnetic sensing device as one of the magnet assembly and the door/window magnetic sensing device approaches the other of the magnet assembly and the door/window magnetic sensing device; provide indication that the door/window magnetic sensing device is approaching or moving away from the magnet assembly corresponding to an increase or decrease in a signal strength of the magnet sensed by the Hall effect sensor; and provide indication that the magnet and the Hall effect sensor are moved to a position that corresponds to the door/window magnetic sensing device and the magnet assembly being in a closed or shut position and the signal strength of the magnet sensed by the Hall effect sensor exceeds a signal strength margin. a Hall effect sensor configured to sense signal strength of a magnet and output a signal strength value, the Hall effect sensor providing an output voltage when no magnetic field is sensed thereby, a controller for receiving the signal strength value from the Hall effect sensor, the controller configured to determine an alarm state, a normal state, and a tamper state from the signal strength value, a wireless transmitter circuit, wherein the controller is configured to control the wireless transmitter circuit to output a normal state wireless signal when the signal strength value is either above an alarm threshold value or below the alarm threshold value depending on an orientation of a magnet that is sensed thereby, a housing with a mounting plate for mounting in surface-to-surface contact with a door frame, a printed circuit board disposed within the housing and oriented transverse to the mounting plate, an indicator, wherein the Hall effect sensor, the controller, the indicator and the wireless transmitter circuit are provided with the printed circuit board and the Hall effect sensor is disposed on the printed circuit board away from the mounting plate, wherein the device is configured to, during installation, use the indicator to provide indication that a magnet assembly and the door/window magnetic sensing device are too far apart to perform door sensing; provide indication that the magnet is being detected by the Hall effect sensor of the door/window magnetic sensing device as one of the magnet assembly and the door/window magnetic sensing device approaches the other of the magnet assembly and the door/window magnetic sensing device; provide indication that the door/window magnetic sensing device is approaching or moving away from the magnet assembly corresponding to an increase or decrease in a signal strength of the magnet sensed by the Hall effect sensor; and provide indication that the magnet and the Hall effect sensor are moved to a position that corresponds to the door/window magnetic sensing device and the magnet assembly being in a closed or shut position and the signal strength of the magnet sensed by the Hall effect sensor exceeds a signal strength margin. provide indication that a magnet assembly and the door/window magnetic sensing device are too far apart to perform door sensing; provide indication that the magnet is being detected by the Hall effect sensor of the door/window magnetic sensing device as one of the magnet assembly and the door/window magnetic sensing device approaches the other of the magnet assembly and the door/window magnetic sensing device; provide indication that the door/window magnetic sensing device is approaching or moving away from the magnet assembly corresponding to an increase or decrease in a signal strength of the magnet sensed by the Hall effect sensor; and provide indication that the magnet and the Hall effect sensor are moved to a position that corresponds to the door/window magnetic sensing device and the magnet assembly being in a closed or shut position and the signal strength of the magnet sensed by the Hall effect sensor exceeds a signal strength margin.