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Supported and Allowed modes are modified to be bitmasks of MM_MODEM_MODE values, and preference of a specific mode is now given in the new PreferredMode property and as an extra argument to the SetAllowedModes() call. * Supported Modes: bitmask specifying which modes are supported by the specific hardware. For example, a modem may only support 1G/2G/3G connections (not 4G). * Allowed Modes: bitmask specifying which modes, of the ones Supported by the modem, are allowed to use. For example, a modem may support 1G/2G/3G connections but only 1G and 2G connections are allowed by the user as 3G involves more expensive data rates. [Allowed] ⊆ [Supported] * Preferred Mode: specific mode which is preferred among the ones defined in the Allowed modes bitmask. For example, a modem may allow 1G/2G/3G connections but the user would like that if possible 2G be used, as 3G consumes too much battery. If 2G is not possible, 3G can be used. [Preferred] ∈ [Allowed]
ModemManager. The problem ModemManager tries to solve is to provide a unified high level API for communicating with (mobile broadband) modems. While the basic commands are standardized, the more advanced operations (like signal quality monitoring while connected) varies a lot. Using. ModemManager is a system daemon and is not meant to be used directly from the command line. However, since it provides DBus API, it is possible to use 'dbus-send' command to control it from the terminal. There's an example program (tests/mm-test.py) that demonstrates the basic API usage. Implementation. ModemManager is a DBus system bus activated service (meaning it's started automatically when a request arrives). It is written in C. The devices are queried from udev and automatically updated based on hardware events. There's a GInterface (MMModem) that defines the modem interface and any device specific implementation must implement it. There are two generic MMModem implementations to support the basic operations (one for GSM, one for CDMA,) which are common for all cards. Plugins. Plugins are loaded on startup, and must implement the MMPlugin interface. It consists of a couple of methods which tell the daemon whether the plugin supports a port and to create custom MMModem implementations. It most likely makes sense to derive custom modem implementations from one of the generic classes and just add (or override) operations which are not standard. There's a fully working plugin in the plugins/ directory for Huawei cards that can be used as an example for writing new plugins. Writing new plugins is highly encouraged! API. The API is open for changes, so if you're writing a plugin and need to add or change some public method, feel free to suggest it!