What Is Radio Data System (RDS)?

Radio Data System (RDS) is a low-speed digital information service carried alongside an FM station’s regular audio, allowing a compatible radio to show details such as the station name, program information, time, song text, or traffic alerts. It does not affect audio quality; it adds data that equipped receivers can decode. This guide explains how RDS works, what its features mean, and how to use or disable it in a car or home radio.

What the Radio Data System Does

RDS is an FM station’s small, one-way information channel, not a replacement for FM audio.

An FM station can broadcast ordinary sound to any FM radio while also sending a small amount of digital data. The audio still works on older radios; those radios simply ignore the extra data.

Depending on the station and receiver, RDS can provide:

The station’s call sign, brand, or format name
A program or show name
Song and artist information
The current time
A program category, such as news, sports, talk, or music
Traffic announcements
Automatic switching to a stronger frequency for the same station network

The information is optional. Not every FM station carries RDS, and stations that do can choose to send different fields of information, according to Sony Support’s RDS overview.

That is why one station may show a full song title and artist while another only shows a short station name.

How RDS Works With an FM Broadcast

RDS data rides on a separate part of an FM stereo broadcast rather than mixing into the music or talk audio. It uses a 57 kHz subcarrier and sends data at 1,187.5 bits per second.

That is a very small data rate by modern standards. It is enough for station identifiers, brief messages, and control information, but not for album art, live web pages, or detailed track metadata.

The station repeatedly sends small data groups. An RDS-equipped receiver decodes those groups, checks them for errors, and updates its display when it receives usable information. Common receiver behaviors include:

Station text can take a moment to appear after tuning.
A song title can remain on screen briefly after the song changes.
Text may scroll because the display is too small for the full message.

The RDS signal is designed to coexist with ordinary FM stereo broadcasting. A non-RDS radio continues to receive the station normally because it does not attempt to decode the data.

How to Use or Turn Off RDS on a Radio

Before changing settings, decide what you want the radio to stop doing. Turning off the RDS text display is different from turning off traffic interruptions or automatic frequency switching.

Your Goal	Feature to Look For	Usual Result
Show station and song information	RDS, Radio Text, Text, Info, Display	Shows available station data
Stop scrolling song or station text	Text display	Changes the text display
Stop the radio changing frequencies	AF, Alternative Frequency	Keeps the radio on the frequency you selected
Stop traffic bulletins interrupting audio	TA, Traffic Announcement	Prevents traffic-alert interruptions
Disable all supported RDS behavior	RDS	Depends on the receiver

Step 1: Confirm That the Receiver Supports RDS

Select the FM radio source on the car stereo, portable radio, receiver, or tuner.
Look for the RDS logo and wording on the radio.
Do not assume that every FM receiver can decode RDS just because it receives FM stations.

For its CDX-GT310MP car stereo, Sony states that radios and tuners marked with the RDS logo and wording can receive and display RDS information. That marking is a useful sign when you are checking whether a particular receiver has the feature.

In the United States, a radio may use the term RBDS instead of RDS. It is closely related to RDS and serves the same practical purpose for listeners.

Step 2: Tune a Strong FM Station and Open the Information Display

Tune to a local FM station with a steady, clear signal.
Use a button labeled Display, Info, Text, RDS, or a similarly named control to cycle through available information screens.
Wait for the receiver to collect and decode the station’s data.
Look for a station name, call letters, program title, clock, song information, or program category.

If the display stays on the frequency, that does not automatically mean the radio is defective. The station may not transmit RDS, or the signal may be too weak for reliable decoding.

Step 3: Disable the Specific RDS Behavior You Do Not Want

Open the radio settings screen.
Turn off the text-display option, if the radio offers one.
If the radio keeps changing to another frequency while you drive, turn off AF or Alternative Frequency.

The exact wording and menu location vary by radio maker and model.

Step 4: Test the Setting Before You Drive

Return to the station you normally use.
Change stations once and tune back to confirm the display or switching behavior has changed.
If the radio has a power button rather than an always-on ignition connection, restart it and confirm the setting remains in place.
Keep the setting that solves the problem without disabling features you still want, such as station identification or the clock.

Common RDS Features and What They Mean

Several common RDS features are useful to recognize.

PS or Program Service: The short station name or identifier. It may show call letters, a format name, or station branding.

RT or RadioText: A longer text field. Stations may use it for song titles, artist names, news headlines, promotions, or program details.

PTY or Program Type: A category describing the station or current program, such as news, talk, sports, rock, classical, or weather. Some radios let you search by program type.

PI or Program Identification: A code that helps the receiver recognize a station or connected station network. It is mainly used behind the scenes for features such as frequency switching.

AF or Alternative Frequency: A feature that can move the radio to another frequency carrying the same program when the current signal gets weak. It is most useful for regional networks and long drives, but it can be annoying if you want to stay on one exact frequency.

TP and TA: Traffic Programme and Traffic Announcement. TP identifies a station that carries traffic information; TA can temporarily interrupt another source or station for an alert.

CT or Clock Time: A time signal that some receivers can use to set or update their clocks. Whether it works reliably depends on whether the station sends it and how the receiver handles it.

Why RDS Is Missing or Behaving Oddly

Start with the station and signal before assuming the receiver has failed.

The Radio Plays Audio but Shows No Station Information

A receiver setting may be preventing the station information from appearing. Try another strong local FM station before changing other settings.

A station can sound clear enough to listen to while its digital RDS data is still too weak or error-prone for the radio to decode.

The Display Shows Old or Incorrect Song Information

The station controls its own RDS text. If its automation system is delayed, misconfigured, or using promotional text instead of track data, the radio will display what the station sends.

The receiver generally cannot correct the station’s metadata. Tune away and back, then compare the display with another RDS-capable receiver if you want to rule out a frozen display.

The Radio Keeps Retuning While Driving

AF is likely enabled. The radio may be searching for a stronger transmitter that carries the same program, but the change can be unwanted near station boundaries or where multiple signals compete.

Turn off AF if you prefer the radio to remain on the frequency you selected.

Traffic Alerts Interrupt Music or Another Audio Source

TA may be enabled. Some radios treat traffic announcements as a priority and briefly interrupt FM, Bluetooth, USB audio, or another source.

Turn off TA or traffic announcements if you do not want those interruptions.

RDS, RBDS, HD Radio, and DAB Compared

RDS and RBDS are closely related FM data systems. RDS is the term used internationally, while RBDS is the North American adaptation. Many U.S. radios still label the feature simply as RDS.

RDS is not the same as HD Radio. HD Radio uses a digital broadcasting system that can carry digital audio and additional services. An FM station may use RDS, HD Radio, both, or neither.

RDS is also not DAB or DAB+. Those are separate digital radio broadcasting systems used in some countries. They do not work as an add-on to a conventional U.S. FM tuner in the way RDS does.

Finally, RDS does not use your phone’s cellular data or Wi-Fi. The information comes from the FM station over the air.

Frequently Asked Questions

What is RDS on a car radio?

RDS on a car radio is the Radio Data System feature that lets an FM station send extra information alongside its normal audio. A compatible stereo may show the station name, song title, program type, time, traffic information, or alternate frequencies.

Why does my car radio change FM frequencies by itself?

Automatic frequency switching, usually labeled AF or Alternative Frequency, is probably enabled. The radio is trying to find a stronger signal for the same station network; turn off AF if you want it to remain on the tuned frequency.

Can RDS show the song title and artist?

Yes, RDS can carry song and artist text through RadioText, often labeled RT or simply Text. Whether it appears depends on the station sending that information and the receiver supporting the display field.

Does RDS use mobile data or cost money?

No. RDS is broadcast over the FM signal and does not use your phone plan, cellular data, Wi-Fi, or a subscription. You only need an RDS-capable FM receiver and a station that transmits the service.

Can I add RDS to an old FM radio?

Usually, no setting can add RDS decoding to a radio that was not built with it. You would need an external tuner or a replacement receiver that supports RDS or RBDS.

Is RDS the same as HD Radio?

No. RDS is a low-speed data service added to conventional FM broadcasts, while HD Radio is a digital broadcast system that can deliver digital audio and extra program services. A station may offer one, both, or neither.