Broadband versus narrowband connections
The term broadband connection is generally understood to mean a data connection with a high throughput rate.
This can be established via fiber optics, cable or radio. The higher the data requirement, the greater the (spectral) bandwidth of the signal.
This relationship is a physical law and cannot be circumvented. An Internet connection via WLAN, HYPERLAN, LTE or UMTS is, for example, a broadband connection. These signal forms enable us to use the modern communication we are used to in metropolitan areas.
On the other hand, there are the narrowband connections, which are usually not referred to as such.
With narrowband connections, little information is transmitted over one channel, e.g. telephone, teletype and fax. A radio voice connection with a remote station would also be such a case. A distinction is made between mono-directional and bidirectional connections. The reception of radio programs is monodirectional because I can only receive the broadcast, but cannot speak to the radio announcer myself. The radio connection with a remote station is naturally bidirectional, i.e. an exchange of information between me and the remote station can take place. In this case, a distinction is made between simplex and duplex connections. A classic telephone connection is, for example, a duplex connection, i.e. both participants can talk and hear at the same time. Whereas with a simplex connection one can only speak or hear alternately.