Documentation/Maemo 5 Developer Guide/Using Multimedia Components/FM Transmitter API Usage
FM Transmitter is controlled by fmtx-middleware program via D-Bus API. API includes functions to enable transmitter, change transmitting frequency and station name. Please note that available frequencies may vary by sales region and FM Transmitter may be disabled in certain sales regions. Transmitter is also disabled when external devices are connected to Maemo device, excluding charger and Bluetooth devices. When FM Transmitter is enabled, fmtx-middleware will route audio automatically to the transmitter and enforce proper transmission power allowed in sales region. Fmtx-middleware will emit beeping tone when no other audio is being transmitter to comply with legislature. Api documentation is in the fmtx-middleware-doc package.
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API documentation
Service: com.nokia.FMTx Interface: com.nokia.FMTx.Device Object path: /com/nokia/fmtx/default
Properties
| version | Uint32 | Read only | Version number of fmtx-middleware
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| frequency | Uint32 | Read/write | Frequency in kHz. Returns DBUS_GERROR_INVALID_ARGS error, if frequency is not allowed
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| freq_max | Uint32 | Read only | Returns maximum allowed frequency in kHz |
| freq_step | Uint32 | Read only | Returns the minimum step between frequencies in kHz |
| state | String | Read/write | Returns the state of the transmitter. States are: enabled – Transmitter is currently enabled disabled – Transmitter is currently disabled error – Internal error while initializing the transmitter, transmitter can’t be enabled. n/a – Transmitter is permanently disabled in this device. State can be set to enabled or disabled. May return DBUS_GERROR_FAILED if transmitter can’t be enabled
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| startable | String | Read only | Returns message about can the transmitter be enabled at current time. Messages are: true Device is in offline mode Headphones are connected USB device is connected |
| rds_ps | String | Read/write | Get/Set RDS text (displayed alternating with station name. Maximum length is 64 characters. Returns DBUS_GERROR_INVALID_ARGS is set text is too long
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| rds_text | String | Read/write | Get/Set RDS text (displayed alternating with station name. Maximum length is 64 characters. Returns DBUS_GERROR_INVALID_ARGS is set text is too long
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Signals
| Changed | None | Some fmtx property was changed |
| Error | String | FM transmitter was disabled by one of the following reasons:
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Properties are manipulated with org.freedesktop.DBus.Properties interface. For more information see D-Bus documentation.