CHICAGO — The Radio Data
System is a data bearer that uses the 57 kHz subcarrier on FM radio broadcasts.
The data is generated by an RDS encoder, which produces groups of RDS
information and adds them to the subcarrier. In its most basic form — providing
on RDS-capable receivers an unambiguous readout of the station name and the
ability to follow from transmitter to transmitter seamlessly — it has been in use
since about 1986 in Europe, and is now used around the world.
Over the last decade in particular,
many broadcasters have chosen to use the RadioText feature to provide details
of on-air songs and artists and other program details, while traffic information
service providers (such as NAVTEQ, part of Nokia) operate a Traffic Message
Channel, providing densely-coded real-time traffic information to navigation
devices to optimize routing.
In TMC, traffic messages are sent as a
series of codes representing locations on the road networks, incidents
(accidents, road work, driving hazards, etc.) and speed of traffic flow on each
road segment. The use of codes provides efficient bandwidth usage of the RDS
bearer, and language/units independent presentation.
To operate “dynamic services” such as
TMC, the RDS encoder needs to comply with the Universal Encoder Communications
Protocol (UECP), which is the command protocol that RDS servers produce. UECP
not only specifies what TMC data will be transmitted, but also how that data
will be interleaved with for other RDS groups — for example RadioText — and how
many times the same data will be transmitted before being discarded.
One of the other important things for
both broadcasters and traffic information service providers is to be able to
monitor the RDS data stream, to confirm the functioning of the encoder, check that
it conforms with the RDS and RDS-TMC specifications and to be able to record
and archive RDS data broadcasts for both use in the event of a query, and to
provide sample data to manufacturers, developing a TMC receiver in Japan, to be
used in Russia, for example.
Werner Drews at 2wcom has been involved
in the development and production of RDS encoders and monitors for almost as
long as RDS itself, and 2wcom’s flagship encoder, the C02, handily fulfills the
needs of a TMC service provider such as NAVTEQ or any other RDS broadcaster.
The main setup of the C02 uses an
intuitive screen GUI configuration application (ARCOS) from which each RDS parameter
(PI, PS, PTY, DI, MS, TP, PTYN, etc.) are configured, as are RDS Group Sequence
(GS) and associated parameters along with communication protocols (ports, etc.)
to connect the encoder to the TMC servers and playout systems.
On the front panel of the 1 RU 19-inch
rack-mount unit, as well as basic LED status indicators, the C02 has a two-line
display and a jog wheel used for initial setup and to check monitoring without additional
software or tools. Its little sister, the C04, is a reduced-price slave model that
lacks the display and jog wheel, but otherwise has the same functionality.
Both encoders can be configured to
self-monitor, and to send email alerts or cause a contact closure if the RDS
data stream or individual parameters are off-normal.
Not only are the 2wcom encoders UECP-compliant,
they also have a built-in decoder. This means that the complete “raw” RDS data
produced by the encoder can be both archived, and by using the accompanying RDS
Lab software, fully decoded, so it can monitored for accuracy. Also, a further
invaluable option for the TMC service provider is the decoding in “plain language”
of the decrypted and decoded TMC messages, providing an instant confirmation of
the correct broadcasting of the TMC content.
The combination of a UECP-compliant
encoder, easy network configuration via the front-panel display and jog-wheel,
and unparalleled decoding and monitoring make the 2wcom C02 a market-leading
RDS Encoder that fully meets all our needs.
is lead architect for NAVTEQ.
information, contact Barbara Petersen at 2wcom Systems in Germany at
011-49-461-6628300 or visit www.2wcom.com.