RBDS: The Forgotten But Useful Technology Standard
February 18, 2011
It seems that all the attention these days is going to digital media and their potential as competitor or complement to broadcasting. Pandora is going public and selling advertising, XM Sirius is trying to do local; radio is seeking a digital platform on mobile devices like the iPhone; and the latest on HD radio have all been topics catching the headlines. What's a simple analog radio station to do?
A recent conversation with a client reminded me that there has been useful technology that has now been around for decades, that could also be very useful in furthering the listener relationship and that has been largely overlooked by broadcasters. This broadcaster was bemoaning the fact that it now has radio stations spanning its mostly rural state. The stations program to the same demo taste. How can I keep a listener as he or she drives across the state, he asked. How do I keep them apprised of the next station to go to?
That's not an uncommon problem in rural areas and suburban areas where broadcasters have acquired multiple Class A FM stations with "rim shot" coverage of a market that could be "strung" together for more comprehensive coverage.
The answer is the AF (Alternate Frequency) code, a component of the Radio Broadcast Data System (RBDS) - the same standard that displays your call sign or frequency on a radio digital display.
Like HD radio, when RBDS was first introduced, there were few receivers that took advantage of its abilities -- and it was before the major revisions to the local ownership rules coming from the Telecommunications Act of 1996. Thus, it was, for the most part, written off by broadcasters. Now that ownership patterns have changed and most automobile receivers have it, few broadcasters have done the look-back, to see how RBDS could be employed to improve their business.
So, here's a review: Radio Broadcast Data System (RBDS) is the official name used for the U.S. version of the Radio Data System, or RDS. RDS is a communications protocol standard for embedding small amounts of digital information in conventional FM radio broadcasts. RBDS was adopted by the National Radio Systems Committee, a joint venture of the Electronic Industries Association and the National Association of Broadcasters. RBDS provides broadcasters significant revenue-producing opportunities by enabling them to offer services which both enhance the appeal of their primary broadcasting service and to provide new ancillary services.
How It Works
RBDS operates on the 57 KHz subcarrier without disturbing SCAs at other locations. It is compatible with and can coexist with HD Radio. Because it is compatible with the European Broadcasting Union's standard RDS, many if its services can be made available worldwide. However, the RDS standard does not include some of the U.S. enhancements, such as the In-receiver Data Base System (IRDS), an in-receiver ROM data base that can be updated via a subcarrier data stream, and MBS/MMBS, the system used by some U.S.-based subcarrier networks for data.
There are 16 different data group types, numbered 0-15, each of which has two different versions, A and B. Different RBDS features are allocated to each group type -- and a few features are common to all groups. Some of the RBDS features have already become second-nature to radio listeners. For example, RBDS sends two blocks of data to carry a "PI" code and a "PTY" code, which provide information identifying the station, its location and the format it is broadcasting and allows that information to be displayed on the user's receiver. It is these codes that allow the receiver to scan by format. As mentioned above, one of the most useful purposes to which RBDS could be put today is the use of the "AF" or alternate frequency code.
Other blocks of data are used to provide additional services, some of which include:
- Radio Text: A 64-character capacity to send text such as advertisements, song titles or other information of a broadcaster's choosing. This information can also be available for sale as advertising. At the time RDBS was introduced, this was thought to be too short for useful messages, but in the modern era of "Tweeting" social messages, Radio Text might be welcomed by the most sought after age demo.
- Clock and Time: Signals can be sent to synchronize the time of receivers with the radio station, and for other uses requiring time.
- Alternate Frequency: A station can inform a receiver to re-tune itself to a broadcaster designated alternate frequency when the presently tuned signal becomes weak. This feature could be harnessed for multiple stations programmed together to cover large distances, established travel routes, enhanced metro coverage, special occasions, simulcasts or any other area-wide group broadcast operations.
- Emergency Alerts: Some RBDS groups may be used to provide emergency messages. When adopted by the NRSC, RBDS was endorsed by the FCC for use by broadcasters in enhancing the then new Emergency Alert System.
- Traffic Alerts: The radiotext or transparent data group could be used to provide traffic announcements, emergency road conditions or snarled traffic alerts. These groups can also be used to power intelligent highway systems for traffic re-routing and intelligent signs.
- Addressable Messaging: Initially employed for subcarrier paging, RBDS offers addressable messaging by either RDS or the more robust MMBS systems. RDS is less robust for data, but allows the subcarrier to be used simultaneously for several other purposes. MMBS carries more data but reduces the utility of RBDS subcarriers for other purposes. Paging was a popular use for RBDS when it was introduced, but has been largely replaced with widespread mobile phone capability. However, other addressable messaging adaptations could utilize this data block.
- Navigation: RBDS may be used to provide navigational beacons to automobiles and watercraft alone or in conjunction with the Global Positioning Satellite System (GPS). This service called "Differential GPS" was displaced when the full GPS satellite system signal was made available to the public, but may still be useful in some special environments.
- Coupon Radio: RBDS can be used to deliver intelligent data "coupons" combined with a variety of delivery techniques, or in conjunction with the station's website.
- Transparent Data: This group can be used to transmit virtually any data to the receiver for downloading to a memory chip for later use or display as radiotext on an LCD. These channels may be used to supplement other RBDS applications or may be used for new forms of advertising and station promotion.
Enterprising entrepreneurs may also conceive of wide-area or nationwide business models that could be implemented with the RBDS capacity of many stations. RBDS leases could be used for this purpose, as they were when subcarrier paging was popular. Subcarrier leasing presents another set of issues, including term, rate, FCC compliance and allocation of liability, all of which are manageable. First, however, radio broadcasters might want to take another look at this resource to determine whether there is a new place in radio's 21st century business plan for this data capable resource.
Here is a link to the latest RBDS standard: http://www.nrscstandards.org/SG/nrsc-4-A%20Standard.pdf
and a link to the members of the NRSC RBDS subcommittee: http://www.nrscstandards.org/RBDS/Member%20list%20RBDS.pdf
This column is provided for general information purposes only and should not be relied upon as legal advice pertaining to any specific factual situation. Legal decisions should be made only after proper consultation with a legal professional of your choosing.