The Broadcaster's Guide to RBDS

Scott Wright

• Publisher: Routledge
• Year: 1997
• ISBN:
  9781136026492
• Edition: 1
• Topic: Sprachen & Linguistik
• Subtopic: Kommunikationswissenschaften

This handbook is intended to give the broadcast industry an authoritative guide to the Radio Data System (RDS), also called Radio Broadcast Data System (RBDS). Since the standard's adoption, about 700 stations have begun broadcasting RDS in the United States. There is a wide variety of encoding equipment with prices starting as low as $400, and over 30 models of RDS receivers have been introduced for cars, home receivers, portable and even PC receivers. Automobile manufacturer's such as General Motors, Ford, Audi, and Porsch now offer RDS on new vehicles. Yet despite all the support equipment in place, the FM broadcaster has been reluctant to implement and utilize this service, mainly because of a lack of understanding of what RDS can do for the station.

This book finally provides the information required to understand RDS and its possibilities on a variety of levels, so that everyone involved in radio can make the most of it. Station owner, program director, salesperson, and talent alike will find the information he or she requires to maximize the possibilities of this new technology.

Each feature of the system is explained in terms of its practical implementation at the station, and interviews with broadcasters currently using the system add a hands-on perspective. Scott Wright is a recognized pioneer in RDS development. As the designer of Delco Electronics' first RDS receiver, he has been extremely active in the development of the RDS standard in the US and in efforts to educate the broadcast community about its potential. He has represented Delco at the European Broadcasting Union's (EBU) RDS Forum and is currently the Chairman of the National Radio Systems Committee RBDS Subcommittee, the US standard-setting body. He is also a member of the Electronics Industries Association's (EIA) RDS Forum.

1
What is RDS, or RBDS, or Smart Radio?

You may have heard any of the above terms; they all basically refer to the same thing. The definitions are as follows:

• RDS—Radio Data System. This is the standard utilized everywhere in the world except North America. All aspects of the RDS standard are encompassed within the RBDS standard.
• RBDS—Radio Broadcast Data System. This technical standard is exactly like the RDS standard, except that additional features have been added that are tailored to the needs of the American broadcaster. RBDS is the name of the standard only. All references should otherwise refer to the technology as RDS.
• Smart Radio. A termed coined by the receiver manufacturer Denon, so that we wouldn't have to remember RDS or RBDS. This is a catchy and descriptive way to market this technology to the consumer.

For the purposes of this book I will use the term RDS. Now, then, RDS is a 57 kHz data subcarrier that transmits advanced radio tuning and program information from the broadcaster to the listener. This subcarrier is injected into the composite signal by use of an RDS encoder. RDS is used only on the FM band and does not require that the station broadcast in stereo. The data rate is approximately 1200 baud (bits per second) and typically requires only 2.0% modulation. The data is transmitted in a continuous cyclic fashion, resulting in a very robust datastream. The data is organized into functional groups so that only pertinent data is transmitted. Information that must always be transmitted appears in every data group for easy decoding by the receiver.

The broadcaster typically enters information into the encoder with the use of a computer and a serial RS-232 link. Most manufacturers provide interface software that runs on an IBM or IBM-compatible computer. If you do not own a computer, you may purchase an encoder with the necessary information already stored into non-volatile memory by the manufacturer. Most encoders offer storage of multiple sets of information typically referred to as data records. Some encoders offer the ability to change the transmitted data record by means of a push-button interface. In all cases, if you need either to enter information that is not already stored or to change previously stored information, then a computer is necessary. If you are constantly entering in new information, then a dedicated personal computer is required. The true success of any information service is that the more dynamic and relevant the information is, the more interesting it is for the listener. It is to your long-term benefit to go "the extra mile" and provide dynamic RDS data to your best asset—your listener.

For the consumer to use the RDS information being broadcast, he or she must purchase a specially-equipped receiver. There are no add-ons or black boxes currently being marketed. Also, for the automated tuning features to be used, RDS must be integrated into the receiver. The RDS receiver uses an RDS decoder Integrated Circuit (IC) that demodulates the subcarrier data into a continuous stream of Logic l's and O's, then passes that stream to a microprocessor. Microprocessors are used in all electronically-tuned receivers today. The microprocessor then decodes the digital information back into its functional group for use by the receiver-tuner, or displays it to the consumer via an alphanumeric display. RDS receivers typically have additional push buttons on the front panel that allow the consumer to select and activate certain features. Just like any other technology, the added cost is proportional to the number of added features. A general rule of thumb is that an RDS receiver will cost approximately 10% more than a standard FM stereo receiver. As more RDS receivers are sold and more manufacturers enter the market, the add-on price may drop somewhat.

Why Should I Implement RDS?

For the broadcaster who must make every penny count, this question usually boils down to "how will I make my money back?" Think back to your last station promotion; just how long after the money was spent did the results last? A week? A month? With an investment of about $2500 you can promote your station for a lifetime. Your station will not be promoted on some obscure billboard or bumper sticker, but exactly where you want it—in front of the listener. If you have any doubt that you won't have any listeners with an RDS receiver, rest assured. Every car manufacturer has an RDS receiver waiting for you. All the major after-market providers have an RDS receiver waiting as well. All the home-receiver manufacturers have an RDS receiver waiting for you. Almost every manufacturer has been supplying RDS receivers to Europe for years. The RDS and RBDS systems are nearly identical. Manufacturers want to sell RDS receivers to your listeners, if you will only provide the service.

The next point to make is that radio broadcasters need a technology boost to remain competitive with other media services. The most recent big advent for FM was stereo, and that wasn't last year. The promise of digital radio is years away, and it will cost a lot more money to both the broadcaster and the listener to obtain this service. Any automation system you tie into RDS will be useable on digital radio services, since digital radio will only expand upon the features of RDS. Digital radio will be compatible with RDS, so your equipment will not become outdated or incompatible. RDS provides both you and your listener with the opportunity to become more interactive with technology and with each other. RDS offers the perfect blend of features, performance, and cost that has put it in the mainstream of acceptable practice across Europe.

What Are the RDS Features?

RDS involves the use of primary and secondary features. Primary features are contained in all the information groups, while secondary features are transmitted only if you are using the feature. This prevents the data capacity from being wasted on unused features. The following is a summary of RDS features.

Listener Features

Program Identification (PI) Code. The PI code is a four-digit hexadecimal code that is unique for each station. The PI code is calculated from the station's call letters, thus no two are alike.¹ The receiver uses the PI code to identify your station rather than the frequency. RDS allows frequency diversity so that if you simulcast on another frequency, the receiver can automatically tune to the strongest station. If you do simulcast, then you will pick one of the stations' PI codes and use it on all the stations. While the PI code is transparent to the user, its proper use is vital to proper receiver operation.

Program Service (PS) Name. The PS Name is the name of your station. It is whatever name you choose to present to your listener. It can be your call letters, such as "WZWZ-FM," or a slogan, such as "Z-93." The PS Name is displayed instead of the frequency on an RDS receiver. When the listener tunes to your station, your station name will be shown on the radio display. The PS Name cannot be over eight characters in length. Any character referenced in the RBDS standard may be used, but special characters may not be displayable on lower-cost British Flag-type displays.² The note appearing at the bottom of Table E.l of the RBDS Standard details which characters are most commonly displayed.

Traffic Program (TP). If you offer your listeners traffic bulletins, then pay particular attention to this feature. The TP identifies your station to the listener as one that offers traffic programs. RDS receivers can automatically tune to stations that offer traffic programs when the user turns on the traffic announcement feature of the radio.

Traffic Announcement (TA). When an actual traffic bulletin is broadcast, then this information bit must be set to a logic "1." The RDS receiver detects this and will automatically stop any playback device that may be in use and return to the FM-tuner mode. Audio adjustments are also automatically made so that if, for instance, the user had the volume muted, the receiver will adjust the volume to a user-preset level. Some means must be employed to control the state of this information bit coincident with the beginning and end of the actual traffic announcement.

Program Type Codes (PTY). This code is used to designate the current program material being broadcast. For example, there are predefined codes for "Country," "Rock," and "Top 40." The RDS receiver can automatically tune to stations by PTY, allowing listeners to find their favorite program without tuning to all available stations. Advanced receivers can even interrupt the listener when the "News" is broadcast using a PTY watch mode.

Program Type Name (PTYN). This feature allows the ultimate in flexibility for the broadcaster who desires to be set out from his or her peers. While the PTY codes are predefined, the PTYN can be any eight characters that the broadcaster desires to further describe the current program. For example, a broadcaster who is currently using the PTY "Personality" may set the PTYN to "Limbaugh" to specify the current program. A "Rock" station may set the PTYN to "Bob&Tom" to describe their morning team. An RDS receiver cannot search by PTYN, but will display the PTYN in place of the PTY once it is tuned to a particular station.

Alternate Frequencies (AF). AF allows the RDS receiver to tune automatically to the best station when multiple transmitters or translators are used. Regional or National programs that are broadcast over large areas can even be linked together, providing the listener with the illusion of one very powerful transmitter. It is possible to link stations only during specific times when the program material is common. The RDS receiver will only tune where you tell it to, and only if the PI code is identical.

Radiotext (RT). Radio text allows you to transmit up to sixty-four characters of information to the listener. Information such as the current artist and song title, station promotional information, local events, and even additional information about the advertiser whose commercial is currently playing can be sent. This is a great tool for interacting with your listeners in a way that was never before possible.

Clock Time and Date. The current clock time and date is transmitted once per minute using this feature. Consumer receivers use this information to keep accurate clock settings.

Emergency Warning System (EWS). The EWS feature allows the transmission of coded emergency information intended for specialized receivers. The FCC recently recognized the capability of this feature, allowing broadcasters to use RBDS within the new Emergency Alert System (EAS). Broadcast EAS equipment can be linked into an RDS encoder for automatic retransmission of EAS information. An alert feature contained within consumer receivers will be activated when an alert code is transmitted.

Data-Related Features

Open Data Channel (ODC). This is the latest and most flexible addition to the RDS standard. In previous years, working groups were formed to determine the best way to add additional data services, such as Differential Correction to the Global Positioning System (DGPS) and even the Emergency Alert System. What these systems had in common was the need for both public (free) and private (fee-based) delivery. Using the few remaining undefined RDS data groups to perform these services proved to be too complex, and coordinated systems could not be agreed upon. All did agree, however, that each data group left undefined was worth its weight in gold, since once all the groups were defined it meant the end of any future expansion to the system.

Thus was born the concept of the open data channel. The open data channel allows the definition of an unused RDS data group based solely on the Application Identification (AID) code. Thousands of AID codes are available, meaning that the remaining data groups could be defined thousands of different ways. The AID codes are internationally assigned and coordinated, so that you (or indeed anyone) can apply for an AID code and start your own data service. The ODC is much more flexible than other data-only groups, such as the transparent data channel, for it can be automatically tuned (by use of the AID) and tracked, regardless of any other data being transmitted. This dynamic, and potentially very profitable, data group will be covered in great detail later in this book.

Transparent Data Channel (TDC). For specialized applications, information of any type can be transmitted by using this data group. For instance, advertising messages could be sent to an electronic billboard using this feature, Virtually any way that you can sell data can be supported by the TDC. Normal car and home receivers do not decode this information.

In-House Application. Data contained in this group is to be used only by the broadcaster. Remote control applications, station telemetry, or paging applications can be supported using this data group.

Radio Paging (RP). Paging services, including those that are numeric or alphanumeric, can be supported utilizing the RDS subcarrier. This is one method for earning revenue from RDS. One company is beginning to build a nationwide paging service at this time and is looking for broadcaster participation.

Traffic Message Channel (TMC). This features allows traffic information to be coded and displayed on consumer receivers so that normal audio bulletins are not required. TMC also utilizes location information such that consumer receivers will display only the traffic information of relevance during a particular trip.

Other Advantages of RDS

The RDS features are quite impressive by themselves. Some other impressive facts that add to the viability of widespread use in the US are:

• Over ten years of consumer use throughout Europe
• Low-cost receivers offered by almost every major manufacturer
  • Automotive
  • Home
  • Portable
  • Personal Computer
  • Pocket Pagers
  • Data-Only Receivers
• Low investment cost of equipment to the broadcaster
  • RDS Encoders
  • Modulation/Data Monitors
  • Automation Equipment
• Potential revenue to the broadcaster
  • Increased listener interaction with the station
  • Possibility to lease part of the RDS subcarrier to a third party providing data services
  • Paging and other data services
  • Electronic Billboards
• Ability to link simulcast transmitters as "one" through use of the alternate frequencies feature
• Potential to share services through use of the Enhanced Other Networks feature

The following chapters will provide further detail of each of these features, as well as detailed descriptions of available products. Detailed implementation instructions will be provided so that your trip into RDS will be quick and easy.

The Importance of Standardization

The fact that there is a standard for RDS means quite a bit. The competition of rival technologies often results in lack of participation by manufacturers and broadcasters alike. The AM stereo standard was one such debacle. When the industry could not arrive at a consensus, the FCC was drawn in to make the decision. Nearly ten years later, the FCC finally did reach a decision. However, in that time-frame, broadcasters failed to make the commitment necessary to convince receiver manufacturers to include the feature in products....