Skip to content

Cellular Configuration

If it is not configured, the cellular interface is presented on the interface list by modem USB address (i.e. 2-1). This 'fake' interface name is completed by 'proper' interface name (e.g., ppp0) when the first modem configuration is submitted.

The cellular interface should be configured by first enabling it in the IPv4 or IPv6 tab, and then setting the Cellular tab. Note that the cellular interface can only be set as WAN using DHCP, Disabled or Not Managed (only for IPv4 connections). The cellular interface configuration options are described below.

Cellular Configuration

The Cellular tab contains the following configuration parameters:

  • Model: specifies the modem model.

  • Network Technology: describes the network technology used by this modem.

    • HSDPA
    • EVDO
    • EDGE

  • Connection Type: specifies the type of connection to the modem.

  • Modem Identifier: provides a unique name for this modem.

  • Interface #: provides a unique number for the modem interface (e.g., an interface # of 0 would name the modem interface ppp0).

  • Dial String: legacy setting that used to help establishing PPP data sessions for GSM-based modems. Deprecated by NetworkManager and not used anymore. Kura will read it and populate the configuration with the correct values but NetworkManager might not honor the setting depending on its version. Typical dial strings are as follows:

    • HSPA modem: atd*99***1#
    • EVDO/CDMA modem: atd#777

  • APN: defines the modem access point name.

    This is an optional parameter. If left empty, the value is automatically picked up from the Mobile Broadband Provider the modem is registered to. If a value is filled, the APN value is explicitly configured.

    To avoid misconfiguration issues, it is strongly recommended to set it manually.

    Note

    APN value configuration

    A good practice is to set the interface status to Disabled and then Enable For WAN when the APN is explicitly set. NetworkManager, indeed, may fallback to the default value if a wrong APN is specified, causing misleading behaviors. This does not happen if the interface is disabled and re-enabled after APN changes.

  • Auth Type: specifies the authentication type.

    • None
    • Auto
    • CHAP
    • PAP

  • Username: supplies the username; disabled if no authentication method is specified.

  • Password: supplies the password; disabled if no authentication method is specified.

  • Modem Reset Timeout: sets the modem reset timeout in minutes. If set to a non-zero value, the modem is reset after n consecutive minutes of unsuccessful connection attempts. If set to zero, the modem keeps trying to establish a PPP connection without resetting. The default value is 5 minutes.

  • LCP Echo Interval: sets the lcp-echo-interval option of the PPP daemon. If set to a positive number, the modem sends LCP echo request to the peer at the specified number of seconds. To disable this option, set it to zero. This option may be used with the lcp-echo-failure option to detect that the peer is no longer connected.

  • LCP Echo Failure: sets the lcp-echo-failure option of the PPP daemon. If set to a positive number, the modem presumes the peer to be dead if a specified number of LCP echo-requests are sent without receiving a valid LCP echo-reply. To disable this option, set it to zero.

GPS

The GPS tab allows the user to enable or disable the GPS module provided by the cellular modem. The available properties are:

  • Enable GPS: enables GPS module for the selected modem.
  • GPS Mode: specifies the GPS mode.
    • UNMANAGED: the GPS device of the modem will be setup but not directly managed, therefore freeing the serial port for other services to use. This can be used in order to perform the setup of the GPS and then have another service (like gpsd) parse the NMEA strings in order to extract the position informations.
    • MANAGED_GPS: the GPS device of the modem will be setup and directly managed (typically by ModemManager) therefore the serial port won't be available for other services to use.

GPS modes availability

GPS modes available for the modem are dependent on the modem model, modem firmware version and ModemManager version installed on the system. Some modes may not be selectable if the modem does not support them.

Therefore, to use the GPS module provided by the cellular modem with Kura's PositionService, the following considerations should be taken into account:

  • The PositionService should be enabled. Serial settings of the PositionService should not be changed; it will be redirected to the modem GPS port automatically.
  • To use the gpsd and serial PositionService providers with the GPS module provided by the cellular modem, the GPS mode should be set to UNMANAGED.
  • To use the modemmanager PositionService provider with the GPS module provided by the cellular modem, the GPS mode should be set to MANAGED_GPS.

Refer to the Position Service section for more information.