3.4.2 GSM Modem Setup

To activate the modem, you will require a dynamic IP Address supplied by the service carrier to be assigned to the modem. They will also provide you with an activated SIM card.


If more support documentation is required to setup the GSM modem, please visit: https://www.digi.com/ products/cellular-solutions/cellular-routers/digi-transport-wr21#productsupport, to browse various support documents.

The following are the steps required to set up the GSM modem:

  1. Attach the antennas to the modem.
  2. Insert your SIM card into the top (SIM 1) spot of the modem, contacts facing down (see illustration below).

inserting gsm modem sim card

Figure 3-9 Inserting SIM Card



There are two SIM card slots in the modem. Install the SIM card in the upper slot, with the chamfered corner inserted first. The contacts should be face down.

  1. Connect an Ethernet cable from the LAN 0 port on the modem to a LAN port on your PC.
  2. To turn the modem on, you will need to use the STS Field Utility. The modem will need to be connected to the STS Edge using the Modem Power Cable, the 12V battery connected to the STS Edge, and the STS Edge connected to the PC using the USB Programming Cable. See Section 4.7.1 for instructions to turn on the modem using the STS Field Utility.
  3. When the modem is powered-up, the LEDs illuminate and a series of diagnostic self-tests is initiated. When the flashing stops, the self-test diagnostic is complete and the modem is ready to be configured.

getting started wizard login

Figure 3-10 Getting Started Wizard Login

  1. Open your web browser and enter the IP Address "" in the URL address bar. The 'Getting Started Wizard' for the modem will open.
  2. Enter the default Username and Password for the modem: username and password, then click "LOG IN".

modem network configuration

Figure 3-11 Modem Network Configuration

  1. From the menu on the left, select "Configuration", then "Network".

configure mobile interface

Figure 3-12 Configure Mobile Interface

  1. Under "Interfaces", select "Mobile". Ensure that SIM position 1 ("1 (PPP1)") is selected in the dropdown menu. Select "Mobile Settings".

mobile settings

Figure 3-13 Mobile Settings

  1. Enter the Service Plan/APN for your cellular service provider (e.g. Rogers APN is "internet.com"). Scroll down, and click "Apply".

serial port settings

Figure 3-14 Serial Port Settings

  1. Under "Interfaces", select "Serial", then "Serial Port 0"
  2. Check "Enable this serial interface". The following settings should be entered:
    • Baud Rate: 115200 bits/second
    • Data Bits: 8
    • Parity: None
    • Stop Bits: 1
    • Flow Control: None
      Scroll down, and click "Apply".


If using an Ethernet connection from the modem to the STS Edge, then steps 11 and 12 are not required, as the settings are automatically applied.


multitx settings

Figure 3-15 MultiTX Settings

  1. Select "MultiTX", then check "enable MultiTX". Select Serial Port "0" from the drop-down menu. Select "TCP" Protocol.

multitx ip and port settings

Figure 3-16 MultiTX IP and Port Settings

  1. In the "Remote Hosts" table, enter the Home Station static IP address in the "Host" field. In the "Port" field, enter either "49152", "49200", or "49800" depending on your setup and Operating System. When finished, click Apply.
  2. Note:

    It is recommended to set the TCP Port to 49200 if using a Windows 7 or 10 computer, and 49800 if using Windows 8.

  3. From the menu on the left, select "Reboot" to apply the settings to the modem. Once complete, click "Logout".
  4. In the STS Field Utility, Modem Port Settings tab, enter the same settings for the Baud Rate, Data Bits, Parity, Stop Bits, and Flow Control, as well as IP and Port numbers. See Section 4.7.2.

The modem is now configured and ready to be used with the STS Edge Telemetry System.