Globalstar Product Management – Technical Support

Change Baud Rate of GSP-1720 Data Port

How to change the Data_Port baud rate on GSP-1720:

  1. Pre-Requisites:
    • GSP-1720 antenna
      • Does NOT have to be connected
      • Does NOT have to have a view of the sky
      • If an Active Antenna is being used, the 7VDC does NOT have to be applied to pin 22
    • GSP-1720 Power
      • GSP-1720 must be powered on via +5VDC applied to pin 15
      • Connect POWER_ENABLE_N (Pin 13) to ground so that modem leaves the STANDBY state and enters IDLE state
      • IMPORTANT: Do not send any data to the modem for at least 12 seconds after grounding POWER_ENABLE_N (Pin 13)
    • Computer for Reconfiguring GSP-1720 default Data_Port baud rate
      • Terminal Emulator program (e.g., MTTTY) must be running on the computer
      • Data_Port of GSP-1720 must be connected to the serial port of the interface computer
      • Data_Port_DTR must be asserted by the connected computer so that the GSP-1720 will activate the AT command processor
  1. Reconfigure the GSP-1720 for a different bootup Data_Port Baud Rate:
    • From within the Terminal Emulator program, issue AT and wait for the GSP-1720 to respond with “OK”
      • to confirm that the Data Port is active
      • to confirm that you have your terminal emulator set to the correct baud rate.
    • Change the GSP-1720 Data_Port baud rate to xxxxx bps using the AT+IPR command
      • Issue AT+IPR=xxxxx (wait for “OK”)
    • Save the new baud rate into Parameter Profile #1
      • Issue AT&W1 (wait for “OK”)     to write the parameters to GSP-1720 Parameter Profile #1
    • Load the newly saved Parameter Profile into the GSP-1720 and identify this profile as the new default boot configuration for the GSP-1720
      • Issue ATZ1 (wait for “OK”) to load Parameter Profile #1 into the GSP-1720 as the new default bootup parameter profile
      • NOTE – It is possible that the modem will stop responding after you enter ATZ, before you get to the “1”. This is because your terminal program will still be using the original baud rate, rather than the new baud rate.  Do not be concerned.
    • Confirm the new Data_Port baud rate
      • Within the Terminal Emulator program, change the speed of the COM port to the new data rate, xxxxx bps as entered above (in step #2.2.1)
        • NOTE that some terminal emulator programs, such as MTTTY and RealTerm, allow the speed of the interface port to be changed while still keeping the port open
      • Re-Issue the ATZ1 command (wait for “OK”)
  1. Write the new GSP-1720 Configuration to the GSP-1720 NVRAM
    • Release VEXT_ON_N (Pin 13) from electrical ground, so its voltage will “float”
      • This commands the GSP-1720 to write all profiles, selected configuration variables and many important system access parameters to NVRAM
      • After the GSP-1720 has successfully updated NVRAM, it will enter STANDBY mode
      • WAIT 20-25 seconds for modem to go through the transition from ON==>STANDBY mode, writing all required parameters to NVRAM
      • DATA_SILENCE mode: Do not send any information to any of the GSP-1720 interface ports during the 25-second transition to STANDBY mode
    • After the graceful transition of the GSP-1720 from ON ==> STANDBY mode, the new baud rate will have been successfully stored into NVRAM and the Data_Port parameter profile #1 will be identified as the default boot configuration for the GSP-1720
  2. Finish Up
    • Turn off the power to the GSP-1720


The next time that the GSP-1720 modem is powered on, and brought from STANDBY to IDLE mode, the GSP-1720 will use the newly saved Data_Port profile to configure the Data_Port and you will see that the baud rate has been changed to the desired value



Additional keywords:  1720, sdvm

Written by Joseph Crowley

April 16, 2017 at 11:11 pm

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