Manual page for radio_recv(6)
radio_recv - radio receive utility
This program is furnished on an AS IS basis as a demonstration
of audio applications programming.
is the Radio Free Ethernet (RFE) receiver.
(For an overview of Radio Free Ethernet, refer to the
is normally initiated directly by the window-based
program, it may also be used directly as a command-line program,
or in conjunction with a user-written window-based tool.
In Normal Mode (the default case),
is initiated with a set of receiver options specified on the command line.
The program immediately begins scanning the network for radio broadcasts
according to the currently selected options. The program will terminate
on receipt of a
(control-C). Once the receiver tunes in a broadcasting station,
the program will exit when the station signs off.
is specified on the command line,
operates in Command Mode. In this mode, the program reads and processes
command options from
and writes error and status information to
Window-based tools use Command Mode to control the receiver program
and receive status information for display. When operating in Command Mode,
requires that an output device be specified explicitly,
command must be issued to initiate radio reception.
The receiver options are described below. If an option requires a value,
the option name must be followed by an equal sign (=) and the value.
If an option takes a
value, the default is
if the value is missing or poorly constructed.
- Station=[call letters]
This option specifies the station call letters of a radio station to tune in.
A maximum of four characters may be specified. If the receiver is enabled
without specifying a station, the receiver will tune in the first station
that is transmitting audio data.
- Output=[audio device name]
This option specifies the audio output device.
In Normal Mode, the audio output defaults to
When the receiver tunes in a radio station, it assumes exclusive control
of the audio output device. If another process attempts to claim the
audio device for output, it will fail (or suspend until the device is released).
In such cases, the
program may be notified that another process is competing for the audio output
If the Release option is enabled, the receiver will automatically
release the audio device when such notification occurs, allowing other
processes the opportunity to claim the device. As long as the device
remains unavailable, the receiver will throw away any radio broadcast packets
that are detected. When the device is available again, the receiver will
reclaim it and continue playing the incoming audio data. If the Release
option is disabled,
will maintain exclusive control of the audio device until it is explicitly
stopped or the incoming radio station signs off.
The Release option is enabled by default.
This option is used to configure the
Multicast address that the
program uses to locate radio broadcasts. The value may either be a
hostname (which is translated into an
Multicast address by looking up the
name in the
map) or a specific numeric
Multicast address. The special hostname
may be used to force the program to scan only for
Multicast address is designated by the hostname
manual page contains more information on the
- Service=[service|port number]
This option is used to configure the
protocol port number used to
identify Radio Free Ethernet network packets. The value may be either a
service name (which is translated into a port number by looking up the
name in the
map) or a specific numeric port number.
The default port number is designated by the service name
manual page contains more information on configuring the port number.
This option enables the reporting, to
of all changes in the receiver status. This option also enables the
reporting of the active station list. The station list details the state of
all active radio stations, and is output whenever a state change is observed.
The Report option is normally used only in conjunction with Command Mode
to allow the controlling program to maintain state.
This command is used to initiate scanning for a new radio station.
The receiver tunes in to the next radio station whose broadcast is detected.
When multiple stations are actively broadcasting, the scan cycles through
them all before repeating a station. Note that stations whose broadcast
is being squelched due to a silent input signal are not tuned in.
This command is used to initiate radio reception according to the current
parameter settings. It is provided for Command Mode; the receiver
is enabled by default in Normal Mode.
This command is used to turn off the receiver. Queued audio data is
flushed so that audio output stops immediately.
The Stop command is provided for the Command Mode operation.
This command causes the
program to exit.
It is provided for the Command Mode operation.
Created by unroff & hp-tools.
© by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97