Important information for migration from GM862 to R-GM862

  • 1 General remarks


    For proper operation of the
    replacement modules all mounting pins of the R-GM862 must be soldered
    to GND of the PCB as required also by the original module Telit
    GM862.


    If not all mounting pins are
    connected to Ground TDMA noise might occur during voice calls


    All R-GM862 modules providing a
    Python interpreter.


    2 R-GM862-Q4: Replacement for Telit



    GM862-QUAD/PYTHON


    The R-GM862-Q4 is fully pin
    compatible to the GM862-QUAD or R-GM862-PYTHON. All voltage levels
    are similar to the original GM862 module


    The R-GM862-Q4 uses the Telit
    GE864-QUAD as GSM core engine. The standard AT interface of the
    original GM862 modules is “SELINT=1” while the standard AT
    interface of the R-GM862-Q4 is “SELINT=2”.


    You can change the AT interface with
    the AT command “AT#SELINT=1”.


    3 R-GM862-G4E: Replacement for Telit GM862-GPS


    This is module transmits the GPS NMEA
    data via its 2nd UART.



    3.1 GPS compatibility


    The R-GM862-G4E uses the SiRF IV
    chipset for GPS functionality. This increases the total performance
    of the GPS part including sensitivity, TTFF, power consumption, etc.
    compared to the original GM862-GPS.


    The following AT commands are no
    longer supported:

    • AT$GPSAI (reading the antenna
      current)
    • AT$GPSAV (reading the antenna
      voltage)
    • AT$GPSAP (antenna current
      protection)
    • AT$GPSS (NMEA UART baudrate)



    The best compatibility can be
    achieved issuing the following AT commands:

    • AT$GPSNMUN=1
    • AT$GPSP=1
    • AT$GPSD=0
    • At$GPSSAV (save setting in NV)


    3.2 AT Interface
    The R-GM862-GPS provides only the SELINT=2
    interface. Therefore, please test the module with your controller
    software prior to serial production use.


    The current AT-Reference Manual can be downloaded
    here: www.roundsolutions.com/techdocs



    3.3 I/O Voltage levels
    The maximum I/O voltage has been reduced from 3.3V
    to 3.1V. Please test the module before use in production systems
    regarding of the voltage levels and implement necessary adjustments.



    4 R-GM864-G4I


    The R-GM862-G4E uses the SiRF IV
    chipset for GPS functionality. This increases the total performance
    of the GPS part including sensitivity, TTFF, power consumption, etc.
    compared to the original GM862-GPS.


    The best compatibility can be
    achieved issuing the following AT commands:

    • AT$GPSAT=1 (activate power
      supply for GPS antenna)


    • AT$GPSSAV (save setting in NV)



    4.1 I/O Voltage levels


    The maximum I/O voltage has been
    reduced from 3.3V to 3.1V. Please test the module before use in
    production systems regarding of the voltage levels and implement
    necessary adjustments.