| (57) Message elements are formed, consisting of 64 characters, and a succession of groups
of information bits is modulated on the supplementary subcarrier, each group comprising
a code adapted to identify it as a text-containing group, a preset number of characters
constituting a segment of the message element and a four-bit address adapted to locate
said segment within the complete element, according to the RDS system of the European
Broadcasting Union. According to the invention, for the transmission of a message
longer than 64 characters the complete message is segmented into portions of no more
than 60 characters and message elements are formed, to be transmitted in successive
groups, associating with each successive portion a prefix of four control characters
thus composed:
a) a message identifier character, susceptible of assuming one of two configurations
and adapted to maintain the same configuration in the successive groups of bits for
the duration of a same message, and of assuming the other configuration when a different
message begins;
b) a language identifier character, designating the language in which the message
is written;
c) a continuity index character, identifying the message element contained in the
group being transmitted;
d) a message length character, identifying the number of message elements which compose
the complete message.
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