C5 Cellular Config

When building for the C5 Cellular, there are some modem-specific build options that you can choose. These options are set directly in the firmware, in the configuration struct from config.cpp. Some common scenarios are described here.

Building for a particular mobile network (SIM card):

The following five options govern how the modem finds and connects to mobile network(s). These options should be considered whenever you compile the firmware for use with a particular SIM.

  • networkOperatorSettings.allowDataRoaming
    • set to “true” to let the SIM use any network it can find, whether or not the SIM sees it as a “home” network. This is appropriate for many “global” SIM cards, which see all mobile networks as roaming. If you are using a SIM that is tied to a specific carrier, you can set this to “false” to stop the modem from connecting to a foreign network on start-up.
  • networkOperatorSettings.operatorSelectMode
    • AUTOMATIC: Find and use any available mobile network which accepts the SIM. The options “PLMN” and “networkType” are ignored in this mode.
    • MANUAL: Find and connect to only the mobile network with a PLMN matching the “PLMN” option, and of the type specified by networkType.
    • DEREGISTER: This mode forces the modem to deregister from the current network. The modem will stay disconnected from any mobile network until the mode changes. Not particularly useful as a connection strategy, but can be used by custom code looking for implement a custom connection strategy.
    • SET_ONLY: Only useful for custom code implementations. Forces the modem to ignore the specified “PLMN” and “networkType”, and to only interpret the format specifier for the network name (which is fixed in this firmware).
    • MANUAL_AUTOMATIC: Modem follows the MANUAL connection strategy. If a suitable network cannot be found, modem falls back to the “AUTOMATIC” connection strategy.
  • networkOperatorSettings.networkDescriptor.PLMN
    • a 5-6 digit number that combines the “mobile country code” (MCC) and “mobile network code” (MNC) to uniquely identify a particular mobile network. Using the PLMN avoids any issues with variations in network text names. For example, 302220 is the PLMN for TELUS. A list of PLMNs is easily found online, e.g. “http://en.wikipedia.org/wiki/Mobile_country_code”.
  • networkOperatorSettings.networkDescriptor.networkType
    • an enumeration that specifies the access technology of the desired mobile network. Generally, “GSM” specifies a 2G network and “UTRAN” specifies a 3G network. A particular mobile network (PLMN) can have both types of networks available for the modem to use.
  • networkDataSettings.APN
    • is the familiar “access point name” the a mobile operator will generally require in order for the device to access data services on the network. It is typically a string like “internet.com” or “apn”.

Setting up GPS signals:

The GPS receiver in the C5 Cellular publishes a GPS message that contains a variety of signals. You can select which signals in this message will be published through the VI, and how often. Note that all of the selected GPS signals share a single publish interval.

The following are available in telit.config.globalPositioningSettings:

  1. To enable/disable GPS functionality, set the “gpsEnable” flag to “true” or “false”.
  2. Set the interval (in milliseconds) to publish the GPS message via “gpsInterval”.
  3. Select the GPS signals you want to include in the published GPS message by setting the appropriate “gpsEnableSignal_gps_” flag. The following signal “enable” flags are available:
    • gpsEnableSignal_gps_time
    • gpsEnableSignal_gps_latitude
    • gpsEnableSignal_gps_longitude
    • gpsEnableSignal_gps_hdop
    • gpsEnableSignal_gps_altitude
    • gpsEnableSignal_gps_fix
    • gpsEnableSignal_gps_course
    • gpsEnableSignal_gps_speed
    • gpsEnableSignal_gps_speed_knots
    • gpsEnableSignal_gps_date
    • gpsEnableSignal_gps_nsat

Server connection settings:

The following configuration options tell the server how to connect to your OpenXC web server:

  • serverConnectSettings.host
    • the web server address, for example “openxcserverdemo.azurewebsites.net”. Only supply the base address of the web server here, do not include any particular resources (e.g. /api/{IMEI}/data). Specific, standard OpenXC resources are requested by the firmware’s server API calls.
  • serverConnectSettings.port
    • simply the TCP/IP port on which the web service operates. Typically this is port 80 (HTTP).

Socket connection settings:

More advanced settings that control the specific behaviour of the TCP/IP sockets used to communicate with thr OpenXC web server. You typically do not have to modify these unless you have some specific network issues or advanced requirements (or you find the default values to be less than optimal). TCP/IP socket settings are:

  • socketConnectSettings.packetSize
    • the TCP/IP packet size. Set to 0 for default (300 bytes).
  • socketConnectSettings.idleTimeout
    • the number of seconds that the modem will tolerate an idle socket before closing it. An idle socket is a socket without any data exchange. Set to 0 for no timeout, and the modem will keep an idle socket open indefinitely. Note that the server on the other end can still close the socket due to it’s own idle timeout (or other) criteria.
  • socketConnectSettings.connectTimeout
    • the duration of time that the modem will attempt to open a socket before timing out. The duration is specified in “hundreds of milliseconds”, so a value of 600 would be 60000 milliseconds, or 60 seconds. A longer timeout period allow the modem a higher chance of gaining access to the server in a single connect request, at the expense of hanging the command interface for the duration of the timer (other parallel operations cannot be performed). Shortening the timer will increase the odds of a failed connection attempt, but the command interface will become more responsive.
  • socketConnectSettings.txFlushTimer
    • the duration of time that the modem will hold a partial TCP/IP packet before flushing it to the TCP/IP socket. Specified in “hundreds of milliseconds”.