DLT Request for Radio Data System (RDS)

[Jonathan Brucker <jonathan.brucke () gmail com>]

I am posting to request a value for DLT_RDS and LINKTYPE_RDS.

Radio Data System (RDS) is a communications protocol standard
published in 1992 for embedding small amounts of digital information
in conventional FM radio broadcasts.

The standard is also known as Radio Broadcast Data System (RBDS) in the US.

References and Specifications:
https://en.wikipedia.org/wiki/Radio_Data_System
http://www.nrscstandards.org/SG/nrsc-4-B.pdf
http://www.rds.org.uk/2010/RDS-Specification.htm

Thanks,
Jonathan Brucker.


RDS Packet Structure

+---------------------------+
|  RDS Information Word 1   |
|         (2 Octets)        |
+---------------------------+
|  RDS Information Word 2   |
|         (2 Octets)        |
+---------------------------+
|  RDS Information Word 3   |
|         (2 Octets)        |
+---------------------------+
|  RDS Information Word 4   |
|         (2 Octets)        |
+---------------------------+
|    RDS Offset Symbol 1    |
|         (1 Octet)         |
+---------------------------+
|    RDS Offset Symbol 2    |
|         (1 Octet)         |
+---------------------------+
|    RDS Offset Symbol 3    |
|         (1 Octet)         |
+---------------------------+
|    RDS Offset Symbol 4    |
|         (1 Octet)         |
+---------------------------+


Description:

Note: the RDS frame is also known as a "group" in the RDS standard.

The RDS frame consists of 4 RDS Information Words, each 16 bits,
followed by 4 Offset Symbols, each 8 bits, for a total of 12 octets.

The Information Words are as specified in the RDS standard.
Encoding is Big-Endian, as in the standard.

The Offset Symbols are ASCII characters representing the detected
syndromes for the corresponding Information Words, and are used in
the interpretation of Information Words, as per RDS standard.

The valid Offset Symbols are:

Offset | in RDS     | bit sequence
Symbol | Standard   | in RDS standard
-------|------------|----------------
"A"    | A          | 0011111100
"B"    | B          | 0110011000
"C"    | C          | 0101101000
"c"    | c' (C-TAG) | 1101010000
"D"    | D          | 0110110100
"E"    | E (MMBS)   | 0000000000

(from US RBDS Standard 1998, tables P.2, P.3)

Sample Frames:

d3 93 05 c8 e1 17 57 44 41 42 43 44
d3 93 05 c9 e1 17 52 20 41 42 43 44
d3 93 05 ca e1 17 33 20 41 42 43 44
d3 93 05 cf e1 17 20 20 41 42 43 44

The preceding 4 frames encode the following station:
* Program Identification (PI) = 0xd393
* Station Name = "WDR 3   "
* Alternate Frequency = 89.8 MHz
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