An analyte monitoring system , comprising: a display device ; a sensor configured to take measurements indicative of analyte levels; a sensor electronics unit communicatively coupled to the sensor , the sensor electronics unit configured to: ; receive the measurements indicative of analyte levels from the sensor periodically communicate data indicative of the measurements to the display device using a first communication protocol that is Bluetooth or Bluetooth Low Energy; and receive a transmission to start a sensor session from the display device using a second communication protocol that is near field communication, NFC; the receipt of the transmission starting the periodic communications of data indicative of the measurements to the display device ; wherein the display device is configured to: send the transmission to the sensor electronics unit using the second communication protocol; and periodically receive the data indicative of the measurements from the sensor electronics unit using the first communication protocol and perform alarming based on the data indicative of the measurements received from the sensor electronics unit , wherein the sensor electronics unit is configured to start the periodic communications of the data indicative of the measurements after a predetermined time delay after the transmission using NFC, the predetermined time delay being set by the sensor electronics unit . a display device ; a sensor configured to take measurements indicative of analyte levels; a sensor electronics unit communicatively coupled to the sensor , the sensor electronics unit configured to: ; receive the measurements indicative of analyte levels from the sensor periodically communicate data indicative of the measurements to the display device using a first communication protocol that is Bluetooth or Bluetooth Low Energy; and receive a transmission to start a sensor session from the display device using a second communication protocol that is near field communication, NFC; the receipt of the transmission starting the periodic communications of data indicative of the measurements to the display device ; ; receive the measurements indicative of analyte levels from the sensor periodically communicate data indicative of the measurements to the display device using a first communication protocol that is Bluetooth or Bluetooth Low Energy; and receive a transmission to start a sensor session from the display device using a second communication protocol that is near field communication, NFC; the receipt of the transmission starting the periodic communications of data indicative of the measurements to the display device ; wherein the display device is configured to: send the transmission to the sensor electronics unit using the second communication protocol; and periodically receive the data indicative of the measurements from the sensor electronics unit using the first communication protocol and perform alarming based on the data indicative of the measurements received from the sensor electronics unit , send the transmission to the sensor electronics unit using the second communication protocol; and periodically receive the data indicative of the measurements from the sensor electronics unit using the first communication protocol and perform alarming based on the data indicative of the measurements received from the sensor electronics unit , wherein the sensor electronics unit is configured to start the periodic communications of the data indicative of the measurements after a predetermined time delay after the transmission using NFC, the predetermined time delay being set by the sensor electronics unit . <EOS>