Radio Data System
Encyclopedia : R : RA : RAD : Radio Data System
Radio Data System, or RDS, is a standard from the European Broadcasting Union for sending small amounts of digital information using conventional FM radio broadcasts. The RDS system standardises several types of information transmitted, including time and station identification. RDS is standard in Europe since the early 90s, but less so in North America.
Radio Broadcast Data System is the official name used for the U.S. version of RDS, though the "RDS" name seems to be at least as common in usage. The two standards are nearly identical, with only slight differences, mainly in which numbers are assigned to each of 31 musical and other programme formats the RBDS system can identify. RBDS was approved by the NRSC, RDS by the EBU.
Both use a 57kHz subcarrier to carry data at 1187.5 bits per second. The 57kHz was chosen for being the third harmonic (3×) of the pilot tone for FM stereo, so it would not cause interference or intermodulation with it, or with the stereo difference signal at 38kHz (2×). The data format utilises error correction. RDS defines many features (see below), including how private (in-house) or other undefined features (such as differential GPS) can be "packaged" in unused programme groups.
Content and implementation
The following information fields are normally contained in the RDS data:
- AF, Alternate frequencies. This allows a receiver to re-tune to a different frequency providing the same station when the first signal becomes too weak (e.g. when moving out of range). This is often utilised in car stereo systems.
- CT, Clock Time. Can synchronise a clock in the receiver or the main clock in a car.
- EON, Enhanced Other Networks. Allows the receiver to monitor other stations for traffic broadcasts.
- PI, Program Identification. This is the unique code that identify the station. Every station receives a specific code with a country prefix.
- PS, Programme Service. This is simply an eight-character static display that represents the call letters or station identity name. Most RDS capable receivers display this information and, if the station is stored in the receiver's presets, will cache this information with the frequency and other details associated with that preset.
- PTY, Program Type. This coding of up to 31 pre-defined programme types – e.g. (in Europe): PTY1 News, PTY6 Drama, PTY11 Rock music – allows users to find similar programming by genre. PTY31 seems to be reserved for emergency announcements in the event of natural disasters or other major calamities.
- REG, Regional links. This is mainly used in countries where national broadcasters run "region-specific" programming such as regional opt-outs on some of their transmitters. This functionality allows the user to "lock-down" the set to their current region or let the radio tune into other region-specific programming as they move into the other region.
- RT, Radio Text, Radiotekst. This function allows a radio station to transmit free-form textual information that can be either static e.g. station slogans or in sync with the programming such as the title and artist of the currently-playing song.
- TA, TP, Travel announcements, Traffic Programme. The receiver can often be set to pay special attention to this flag and e.g stop the tape or retune to receive a Traffic bulletin. The TP flag is used to allow the user to find only those stations that regularly broadcast traffic bulletins whereas the TA flag is used to stop the tape or raise the volume during a traffic bulletin.
- TMC, Traffic Message Channel. Demands a RDS-TMC decoder.
Program Types
The following table lists the RDS and RBDS Program Type codes and their meanings:
| PTY code | RDS Program type | RBDS Program type |
|---|---|---|
| 0 | No program type or undefined | No program type or undefined |
| 1 | News | News |
| 2 | Current affairs | Information |
| 3 | Information | Sports |
| 4 | Sport | Talk |
| 5 | Education | Rock |
| 6 | Drama | Classic Rock |
| 7 | Culture | Adult Hits |
| 8 | Science | Soft Rock |
| 9 | Varied | Top 40 |
| 10 | Pop Music | Country |
| 11 | Rock Music | Oldies |
| 12 | M.O.R. Music | Soft |
| 13 | Light classical | Nostalgia |
| 14 | Serious classical | Jazz |
| 15 | Other Music | Classical |
| 16 | Weather | Rhythm and Blues |
| 17 | Finance | Soft Rhythm and Blues |
| 18 | Children’s programmes | Language |
| 19 | Social Affairs | Religious Music |
| 20 | Religion | Religious Talk |
| 21 | Phone In | Personality |
| 22 | Travel | Public |
| 23 | Leisure | College |
| 24 | Jazz Music | Unassigned |
| 25 | Country Music | Unassigned |
| 26 | National Music | Unassigned |
| 27 | Oldies Music | Unassigned |
| 28 | Folk Music | Unassigned |
| 29 | Documentary | Weather |
| 30 | Alarm Test | Emergency Test |
| 31 | Alarm | Emergency |
See also
External links
- [A book on RDS] "RDS: Radio Data System (Mobile Communications Library)"
- [The RDS Forum is the professional association of the users of the Radio Data System broadcast technology]
- [RDS List]
- [BBC factsheet - Radio Data System (RDS) in HTML format]
- [RDS-forum] on Yahoo
- [RDS: "The Radio Data System", "The Broadcasters Guide to RDS"]
- [RDS Features Serving as Tuning Aids]
- [68hc11 based RDS decoder], [Alternative address]
- [RDS daemon for Video4Linux radios]
- [Carsten Groß: My RDS decoder and homemade computer]
- [(16F84 baseret) Hollies RDS decoder]
- [FM MEDIA PLAZA]
- [European FM Handbook 2002-2003, The Directory of European FM Broadcasting!]
- Open Directory Project: [DX and Radio Groups]
- [RDS Tuner project]
- [RDS Decoder for Windows]
- [RDS-TMC Decoder]
- [(Scroll a little bit down): ADS Announces World's Most Complete RDS/RBDS/MBS Decoder Chip (RDX-1187c)]
- [RDS Finland]
- [Stations using RDS in West Virginia]
- [RDS Modulator (in polish)]
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