com.sun.spot.io.j2me.radiogram
Class Radiogram

java.lang.Object
  com.sun.spot.io.j2me.radiogram.Radiogram

All Implemented Interfaces:

DataInput, DataOutput, Datagram

public class Radiogram
extends Object
implements Datagram

Helper class for "radiogram:" connections. This class implements Datagram for communication between Spots. You should NOT normally instantiate this class directly, but rather via the GCF framework: see the first reference below for more details.

See Also:

RadiogramConnection

Field Summary

static int

MAX_LENGTH Maximum nuber of bytes that can be stored in a radiogram.

Constructor Summary

Radiogram(int size, Protocol connection, long timeout)

Radiogram(int size, Protocol connection, String addr, long timeout)

Method Summary

int	available()
String	getAddress() Return the address associated with this Radiogram.
Protocol	getConnection()
int	getCorr() CORR measures the average correlation value of the first 4 bytes of the packet header.
byte[]	getData() Not implemented
int	getLength() Return the number of bytes of data in this radiogram
int	getLinkQuality() Link Quality Indication (LQI) is a characterization of the quality of a received packet.
int	getOffset() Get the offset.
byte[]	getPayload() Returns the contents of the radiogram as a byte array
int	getRssi() RSSI (received signal strength indicator) measures the strength (power) of the signal for the packet.
boolean	readBoolean() Reads one input byte and returns true if that byte is nonzero, false if that byte is zero.
byte	readByte() Reads and returns one input byte.
char	readChar() Reads an input char and returns the char value.
double	readDouble() Reads a 64 bit double.
float	readFloat() Reads a 32 bit float.
void	readFully(byte[] b) Reads some bytes from an input stream and stores them into the buffer array b.
void	readFully(byte[] b, int off, int len) Reads len bytes from an input stream.
int	readInt() Reads four input bytes and returns an int value.
long	readLong() Reads eight input bytes and returns a long value.
short	readShort() Reads two input bytes and returns a short value.
int	readUnsignedByte() Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255.
int	readUnsignedShort() Reads two input bytes and returns an int value in the range 0 through 65535.
String	readUTF() Reads in a string that has been encoded using a modified UTF-8 format.
void	receive() Receive into this radiogram
void	reset() Ensures that the next read or write operation will read/write from the start of the radiogram
void	send() Send this radiogram
void	setAddress(Datagram reference) Set the address associated with this radiogram by copying it from the supplied radiogram.
void	setAddress(String addr) Set the address associated with this radiogram.
void	setData(byte[] buffer, int offset, int len) Not implemented
void	setLength(int len) Not implemented
int	skipBytes(int n) Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes.
void	write(byte[] b) Writes to the output stream all the bytes in array b.
void	write(byte[] b, int off, int len) Writes len bytes from array b, in order, to the output stream.
void	write(int b) Writes to the output stream the eight low-order bits of the argument b.
void	writeBoolean(boolean v) Writes a boolean value to this output stream.
void	writeByte(int v) Writes to the output stream the eight low- order bits of the argument v.
void	writeChar(int v) Writes a char value, which is comprised of two bytes, to the output stream.
void	writeChars(String s) Writes every character in the string s, to the output stream, in order, two bytes per character.
void	writeDouble(double v) Writes a 64 bit double.
void	writeFloat(float v) Writes a 32 bit float.
void	writeInt(int v) Writes an int value, which is comprised of four bytes, to the output stream.
void	writeLong(long v) Writes an long value, which is comprised of four bytes, to the output stream.
void	writeShort(int v) Writes two bytes to the output stream to represent the value of the argument.
void	writeUTF(String str) Writes two bytes of length information to the output stream, followed by the Java modified UTF representation of every character in the string s.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

MAX_LENGTH

public static final int MAX_LENGTH

Maximum nuber of bytes that can be stored in a radiogram.

See Also:

Constant Field Values

Constructor Detail

Radiogram

public Radiogram(int size,
                 Protocol connection,
                 long timeout)

Parameters:

size - - ignored

connection - - the Protocol that is using this radiogram

timeout - - the timeout period in ms to use for receives (<0 = wait for ever, >=0 timeout period)

Radiogram

public Radiogram(int size,
                 Protocol connection,
                 String addr,
                 long timeout)

Parameters:

size - - ignored

connection - - the Protocol that is using this radiogram

addr - - the address to associate with this radiogram

timeout - - the timeout period in ms to use for receives (<0 = wait for ever, >=0 timeout period)

Method Detail

getAddress

public String getAddress()

Return the address associated with this Radiogram. If this radiogram has been received then this is the sender's address. If the address has been set with setAddress(...) then this is the address that was set.

Specified by:

getAddress in interface Datagram

Returns:

the address associated with this Radiogram in dotted hex notation

See Also:

Datagram.setAddress(java.lang.String)

getData

public byte[] getData()

Not implemented

Specified by:

getData in interface Datagram

Returns:

the data buffer

See Also:

Datagram.setData(byte[], int, int)

getLength

public int getLength()

Return the number of bytes of data in this radiogram

Specified by:

getLength in interface Datagram

Returns:

the number of bytes of data

See Also:

Datagram.setLength(int)

getOffset

public int getOffset()

Description copied from interface: Datagram

Get the offset.

Specified by:

getOffset in interface Datagram

Returns:

always returns 0 because offsets are not used for radiograms

setAddress

public void setAddress(String addr)

Set the address associated with this radiogram. This is normally the destination address to which the radiogram will be sent.

Specified by:

setAddress in interface Datagram

Parameters:

addr - the address in dotted hex or as a simple integer

See Also:

Datagram.getAddress()

setAddress

public void setAddress(Datagram reference)

Set the address associated with this radiogram by copying it from the supplied radiogram. This is normally the destination address to which the radiogram will be sent.

Specified by:

setAddress in interface Datagram

Parameters:

reference - the radiogram from which the address is to be copied

See Also:

Datagram.getAddress()

setLength

public void setLength(int len)

Not implemented

Specified by:

setLength in interface Datagram

Parameters:

len - the new length of the data

See Also:

Datagram.getLength()

setData

public void setData(byte[] buffer,
                    int offset,
                    int len)

Not implemented

Specified by:

setData in interface Datagram

Parameters:

buffer - the data buffer

offset - the offset into the data buffer

len - the length of the data in the buffer

See Also:

Datagram.getData()

reset

public void reset()

Ensures that the next read or write operation will read/write from the start of the radiogram

Specified by:

reset in interface Datagram

available

public int available()
              throws IOException

Throws:

IOException

readFully

public void readFully(byte[] b)
               throws IOException

Description copied from interface: DataInput

Reads some bytes from an input stream and stores them into the buffer array b. The number of bytes read is equal to the length of b.

This method blocks until one of the following conditions occurs:

• b.length bytes of input data are available, in which case a normal return is made.
• End of file is detected, in which case an EOFException is thrown.
• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[0], the next one into b[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes of b have been updated with data from the input stream.

Specified by:

readFully in interface DataInput

Parameters:

b - the buffer into which the data is read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws IOException

Description copied from interface: DataInput

Reads len bytes from an input stream.

This method blocks until one of the following conditions occurs:

• len bytes of input data are available, in which case a normal return is made.
• End of file is detected, in which case an EOFException is thrown.
• An I/O error occurs, in which case an IOException other than EOFException is thrown.

If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.

Specified by:

readFully in interface DataInput

Parameters:

b - the buffer into which the data is read.

off - an int specifying the offset into the data.

len - an int specifying the number of bytes to read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

skipBytes

public int skipBytes(int n)
              throws IOException

Description copied from interface: DataInput

Makes an attempt to skip over n bytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned.

Specified by:

skipBytes in interface DataInput

Parameters:

n - the number of bytes to be skipped.

Returns:

the number of bytes skipped, which is always n.

Throws:

EOFException - if this stream reaches the end before skipping all the bytes.

IOException - if an I/O error occurs.

readBoolean

public boolean readBoolean()
                    throws IOException

Description copied from interface: DataInput

Reads one input byte and returns true if that byte is nonzero, false if that byte is zero. This method is suitable for reading the byte written by the writeBoolean method of interface DataOutput.

Specified by:

readBoolean in interface DataInput

Returns:

the boolean value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readByte

public byte readByte()
              throws IOException

Description copied from interface: DataInput

Reads and returns one input byte. The byte is treated as a signed value in the range -128 through 127, inclusive. This method is suitable for reading the byte written by the writeByte method of interface DataOutput.

Specified by:

readByte in interface DataInput

Returns:

the 8-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readUnsignedByte

public int readUnsignedByte()
                     throws IOException

Description copied from interface: DataInput

Reads one input byte, zero-extends it to type int, and returns the result, which is therefore in the range 0 through 255. This method is suitable for reading the byte written by the writeByte method of interface DataOutput if the argument to writeByte was intended to be a value in the range 0 through 255.

Specified by:

readUnsignedByte in interface DataInput

Returns:

the unsigned 8-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readShort

public short readShort()
                throws IOException

Description copied from interface: DataInput

Reads two input bytes and returns a short value. Let a be the first byte read and b be the second byte. The value returned is:

(short)((a << 8) * | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput.

Specified by:

readShort in interface DataInput

Returns:

the 16-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readUnsignedShort

public int readUnsignedShort()
                      throws IOException

Description copied from interface: DataInput

Reads two input bytes and returns an int value in the range 0 through 65535. Let a be the first byte read and b be the second byte. The value returned is:

(((a & 0xff) << 8) | (b & 0xff))
 

This method is suitable for reading the bytes written by the writeShort method of interface DataOutput if the argument to writeShort was intended to be a value in the range 0 through 65535.

Specified by:

readUnsignedShort in interface DataInput

Returns:

the unsigned 16-bit value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readChar

public char readChar()
              throws IOException

Description copied from interface: DataInput

Reads an input char and returns the char value. A Unicode char is made up of two bytes. Let a be the first byte read and b be the second byte. The value returned is:

(char)((a << 8) | (b & 0xff))
 

This method is suitable for reading bytes written by the writeChar method of interface DataOutput.

Specified by:

readChar in interface DataInput

Returns:

the Unicode char read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readInt

public int readInt()
            throws IOException

Description copied from interface: DataInput

Reads four input bytes and returns an int value. Let a be the first byte read, b be the second byte, c be the third byte, and d be the fourth byte. The value returned is:

 
 (((a & 0xff) << 24) | ((b & 0xff) << 16) |
  ((c & 0xff) << 8) | (d & 0xff))
 

This method is suitable for reading bytes written by the writeInt method of interface DataOutput.

Specified by:

readInt in interface DataInput

Returns:

the int value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readLong

public long readLong()
              throws IOException

Description copied from interface: DataInput

Reads eight input bytes and returns a long value. Let a be the first byte read, b be the second byte, c be the third byte, d be the fourth byte, e be the fifth byte, f be the sixth byte, g be the seventh byte, and h be the eighth byte. The value returned is:

 
 (((long)(a & 0xff) << 56) |
  ((long)(b & 0xff) << 48) |
  ((long)(c & 0xff) << 40) |
  ((long)(d & 0xff) << 32) |
  ((long)(e & 0xff) << 24) |
  ((long)(f & 0xff) << 16) |
  ((long)(g & 0xff) <<  8) |
  ((long)(h & 0xff)))
 

This method is suitable for reading bytes written by the writeLong method of interface DataOutput.

Specified by:

readLong in interface DataInput

Returns:

the long value read.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

readUTF

public String readUTF()
               throws IOException

Description copied from interface: DataInput

Reads in a string that has been encoded using a modified UTF-8 format. The general contract of readUTF is that it reads a representation of a Unicode character string encoded in Java modified UTF-8 format; this string of characters is then returned as a String.

First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the readUnsignedShort method . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.

If the first byte of a group matches the bit pattern 0xxxxxxx (where x means "may be 0 or 1"), then the group consists of just that byte. The byte is zero-extended to form a character.

If the first byte of a group matches the bit pattern 110xxxxx, then the group consists of that byte a and a second byte b. If there is no byte b (because byte a was the last of the bytes to be read), or if byte b does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

(char)(((a& 0x1F) << 6) | (b & 0x3F))
 

If the first byte of a group matches the bit pattern 1110xxxx, then the group consists of that byte a and two more bytes b and c. If there is no byte c (because byte a was one of the last two of the bytes to be read), or either byte b or byte c does not match the bit pattern 10xxxxxx, then a UTFDataFormatException is thrown. Otherwise, the group is converted to the character:

 (char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
 

If the first byte of a group matches the pattern 1111xxxx or the pattern 10xxxxxx, then a UTFDataFormatException is thrown.

If end of file is encountered at any time during this entire process, then an EOFException is thrown.

After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a String, which is returned.

The writeUTF method of interface DataOutput may be used to write data that is suitable for reading by this method.

Specified by:

readUTF in interface DataInput

Returns:

a Unicode string.

Throws:

EOFException - if this stream reaches the end before reading all the bytes.

IOException - if an I/O error occurs.

UTFDataFormatException - if the bytes do not represent a valid UTF-8 encoding of a string.

write

public void write(int b)
           throws IOException

Description copied from interface: DataOutput

Writes to the output stream the eight low-order bits of the argument b. The 24 high-order bits of b are ignored.

Specified by:

write in interface DataOutput

Parameters:

b - the byte to be written.

Throws:

IOException - if an I/O error occurs.

write

public void write(byte[] b)
           throws IOException

Description copied from interface: DataOutput

Writes to the output stream all the bytes in array b. If b is null, a NullPointerException is thrown. If b.length is zero, then no bytes are written. Otherwise, the byte b[0] is written first, then b[1], and so on; the last byte written is b[b.length-1].

Specified by:

write in interface DataOutput

Parameters:

b - the data.

Throws:

IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int off,
                  int len)
           throws IOException

Description copied from interface: DataOutput

Writes len bytes from array b, in order, to the output stream. If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are written. Otherwise, the byte b[off] is written first, then b[off+1], and so on; the last byte written is b[off+len-1].

Specified by:

write in interface DataOutput

Parameters:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

Throws:

IOException - if an I/O error occurs.

writeBoolean

public void writeBoolean(boolean v)
                  throws IOException

Description copied from interface: DataOutput

Writes a boolean value to this output stream. If the argument v is true, the value (byte)1 is written; if v is false, the value (byte)0 is written. The byte written by this method may be read by the readBoolean method of interface DataInput, which will then return a boolean equal to v.

Specified by:

writeBoolean in interface DataOutput

Parameters:

v - the boolean to be written.

Throws:

IOException - if an I/O error occurs.

writeByte

public void writeByte(int v)
               throws IOException

Description copied from interface: DataOutput

Writes to the output stream the eight low- order bits of the argument v. The 24 high-order bits of v are ignored. (This means that writeByte does exactly the same thing as write for an integer argument.) The byte written by this method may be read by the readByte method of interface DataInput, which will then return a byte equal to (byte)v.

Specified by:

writeByte in interface DataOutput

Parameters:

v - the byte value to be written.

Throws:

IOException - if an I/O error occurs.

writeShort

public void writeShort(int v)
                throws IOException

Description copied from interface: DataOutput

Writes two bytes to the output stream to represent the value of the argument. The byte values to be written, in the order shown, are:

 (byte)(0xff & (v >> 8))
 (byte)(0xff & v)
  

The bytes written by this method may be read by the readShort method of interface DataInput , which will then return a short equal to (short)v.

Specified by:

writeShort in interface DataOutput

Parameters:

v - the short value to be written.

Throws:

IOException - if an I/O error occurs.

writeChar

public void writeChar(int v)
               throws IOException

Description copied from interface: DataOutput

Writes a char value, which is comprised of two bytes, to the output stream. The byte values to be written, in the order shown, are:

 (byte)(0xff & (v >> 8))
 (byte)(0xff & v)
 

The bytes written by this method may be read by the readChar method of interface DataInput , which will then return a char equal to (char)v.

Specified by:

writeChar in interface DataOutput

Parameters:

v - the char value to be written.

Throws:

IOException - if an I/O error occurs.

writeInt

public void writeInt(int v)
              throws IOException

Description copied from interface: DataOutput

Writes an int value, which is comprised of four bytes, to the output stream. The byte values to be written, in the order shown, are:

 (byte)(0xff & (v >> 24))
 (byte)(0xff & (v >> 16))
 (byte)(0xff & (v >>    8))
 (byte)(0xff & v)
 

The bytes written by this method may be read by the readInt method of interface DataInput , which will then return an int equal to v.

Specified by:

writeInt in interface DataOutput

Parameters:

v - the int value to be written.

Throws:

IOException - if an I/O error occurs.

writeLong

public void writeLong(long v)
               throws IOException

Description copied from interface: DataOutput

Writes an long value, which is comprised of four bytes, to the output stream. The byte values to be written, in the order shown, are:

 (byte)(0xff & (v >> 48))
 (byte)(0xff & (v >> 40))
 (byte)(0xff & (v >> 32))
 (byte)(0xff & (v >> 24))
 (byte)(0xff & (v >> 16))
 (byte)(0xff & (v >>  8))
 (byte)(0xff & v)
 

The bytes written by this method may be read by the readLong method of interface DataInput , which will then return a long equal to v.

Specified by:

writeLong in interface DataOutput

Parameters:

v - the long value to be written.

Throws:

IOException - if an I/O error occurs.

writeChars

public void writeChars(String s)
                throws IOException

Description copied from interface: DataOutput

Writes every character in the string s, to the output stream, in order, two bytes per character. If s is null, a NullPointerException is thrown. If s.length is zero, then no characters are written. Otherwise, the character s[0] is written first, then s[1], and so on; the last character written is s[s.length-1]. For each character, two bytes are actually written, high-order byte first, in exactly the manner of the writeChar method.

Specified by:

writeChars in interface DataOutput

Parameters:

s - the string value to be written.

Throws:

IOException - if an I/O error occurs.

writeUTF

public void writeUTF(String str)
              throws IOException

Description copied from interface: DataOutput

Writes two bytes of length information to the output stream, followed by the Java modified UTF representation of every character in the string s. If s is null, a NullPointerException is thrown. Each character in the string s is converted to a group of one, two, or three bytes, depending on the value of the character.

If a character c is in the range \u0001 through \u007f, it is represented by one byte:

(byte)c 

If a character c is \u0000 or is in the range \u0080 through \u07ff, then it is represented by two bytes, to be written in the order shown:

 (byte)(0xc0 | (0x1f & (c >> 6)))
 (byte)(0x80 | (0x3f & c))
  

If a character c is in the range \u0800 through uffff, then it is represented by three bytes, to be written in the order shown:

 (byte)(0xe0 | (0x0f & (c >> 12)))
 (byte)(0x80 | (0x3f & (c >>  6)))
 (byte)(0x80 | (0x3f & c))
  

First, the total number of bytes needed to represent all the characters of s is calculated. If this number is larger than 65535, then a UTFDataFormatError is thrown. Otherwise, this length is written to the output stream in exactly the manner of the writeShort method; after this, the one-, two-, or three-byte representation of each character in the string s is written.

The bytes written by this method may be read by the readUTF method of interface DataInput , which will then return a String equal to s.

Specified by:

writeUTF in interface DataOutput

Parameters:

str - the string value to be written.

Throws:

IOException - if an I/O error occurs.

getLinkQuality

public int getLinkQuality()

Link Quality Indication (LQI) is a characterization of the quality of a received packet. Its value is computed from the CORR, correlation value. The LQI ranges from 0 (bad) to 255 (good).

Returns:

- LQI value

See Also:

RadioPacket.getLinkQuality()

getCorr

public int getCorr()

CORR measures the average correlation value of the first 4 bytes of the packet header. A correlation value of ~110 indicates a maximum quality packet while a value of ~50 is typically the lowest quality packet detectable by the SPOT's receiver.

Returns:

- CORR value

See Also:

RadioPacket.getCorr()

getRssi

public int getRssi()

RSSI (received signal strength indicator) measures the strength (power) of the signal for the packet. It ranges from +60 (strong) to -60 (weak). To convert it to decibels relative to 1 mW (= 0 dBm) subtract 45 from it, e.g. for an RSSI of -20 the RF input power is approximately -65 dBm.

Returns:

- RSSI value

See Also:

RadioPacket.getRssi()

send

public void send()
          throws NoAckException,
                 ChannelBusyException

Send this radiogram

Throws:

ChannelBusyException

NoAckException

receive

public void receive()
             throws IOException

Receive into this radiogram

Throws:

TimeoutException

IOException

InterruptedIOException - if the connection was closed

getPayload

public byte[] getPayload()

Returns the contents of the radiogram as a byte array

Returns:

a byte array containing the contents of the radiogram

readDouble

public double readDouble()
                  throws IOException

Description copied from interface: DataInput

Reads a 64 bit double.

Specified by:

readDouble in interface DataInput

Returns:

the 64 bit double read.

Throws:

EOFException - If end of file is reached.

IOException - If other I/O error has occurred.

readFloat

public float readFloat()
                throws IOException

Description copied from interface: DataInput

Reads a 32 bit float.

Specified by:

readFloat in interface DataInput

Returns:

the 32 bit float read.

Throws:

EOFException - If end of file is reached.

IOException - If other I/O error has occurred.

writeDouble

public void writeDouble(double v)
                 throws IOException

Description copied from interface: DataOutput

Writes a 64 bit double.

Specified by:

writeDouble in interface DataOutput

Parameters:

v - the double value to be written

Throws:

IOException

writeFloat

public void writeFloat(float v)
                throws IOException

Description copied from interface: DataOutput

Writes a 32 bit float.

Specified by:

writeFloat in interface DataOutput

Parameters:

v - the float value to be written

Throws:

IOException

getConnection

public Protocol getConnection()

Returns:

the Protocol controlling this Radiogram