8
DI
Decoder Information:
This is one of several flags that convey
yes/no or other very basic data. This particular flag tells the
receiver whether the broadcast is monaural, or is being
transmitted in any of several methods of stereo or binaural
broadcasting. As many as 16 encoding options may be
accommodated! This is a rather esoteric function and, thus far,
remains unused both in Europe and in the US.
FFG
Free Format Groups:
A provision has been included in the Model
712 to transmit proprietary data directly within a legitimate RDS
group. This is a special use of the encoder for non-standard
applications. Additional notes can be found on Page 29.
M/S
Music / Speech Switch:
This flag simply indicates whether music
or speech is the primary broadcast programming. The purpose of
this function is not well explained in the respective Standards,
hence it comes as no surprise that it is not widely used.
PI
Program Identification:
This block of data identifies the broadcast
station with a hexadecimal numerical code, which becomes the
digital signature of the station. The code is assigned by the
broadcasting authority in some countries, and in the US is
calculated from a numerical encoding of station call letters. The
receiver processes the PI code to assist automatic tuning features
(station memories), and to prevent false switching to alternative
frequencies that might be shared by broadcasters in nearby
regions.
PS
Program Service Name:
This is the station s street name that
will appear on the receiver faceplate display. The PS can be up to
eight characters in length (including spaces) and can be as simple
as the station s call letters (KWOW or KWOW FM) or a slogan
(NEWSTALK or LIVE 95). The Program Service Name is
automatically displayed, even on automobile receivers, so it is
meant to remain static. Because of driving safety considerations,
broadcasters are discouraged from making the PS dynamic ; that
is, to alternate it between different entries. As a matter of fact, it
is a violation of both the CENELEC and the NRSC standards to
flash or scroll the PS display. Nevertheless, this nefarious
practice is becoming more and more common.
PTY
Program Type:
The PTY data flag identifies the station format
from a collection of pre-defined categories. Many RDS receivers
are able to seek the listener s preferred format automatically.
This means that a car radio can switch from a fading station to a
stronger one that carries the same
variety
of music, though not
the very same program, as provided by AF switching. The PTY
function of RDS helps a broadcaster catch transient audience
share. A listing of the PTY categories is given on Page 25.
Under some programming circumstances, the PTY identifier may be
made dynamic, changing between categories for a station that
dayparts (changes its format for specific time periods). The PTY
code is not meant to change from song to song or to accommodate a
top-of-the-hour newscast, however.
