In the middle of the 1980s, the wideband system arrived, transmitting data in a frequency spectrum of approximately 140-400 kHz. Transmission over a number of frequencies was intended to ensure reliable transmission even with interference frequencies such as those generated by frequency converters. By distributing the signal over a frequency spectrum, however, the strength of a signal on any frequency is lower than with narrowband, meaning that narrowband manufacturers can lay claim to a greater range.
Since the data transmission rate on wideband systems is theoretically 19,200 baud, it is also known as a "high data rate system". However, reports suggest that in practice this speed benefit is barely discernible.
Figure 23: ISO filter specification for wideband and narrowband

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