| 摘要 |
<p>A radio data system transmits message groups comprising four blocks of which the first always carries the programme identification code for the transmitting network (PI(TN)). One type of message group, identified by a corresponding group type code (GT) in block 2 always carries a programme identification code for another network (PI(ON)) in block 4 and carries various corresponding items of information in block 3. Which of these various items is in block 3 is identified by a user code (UC) in block 2. The items of information in block 3 may in particular include alternative frequency codes for the other network identified in block 4.</p> |
