The B refers to the fact that it was the country's second public mobile telephone network, following the A-Netz.
As opposed to its predecessor, it featured direct-dialing (so that human operators were not required to connect calls).
A major limitation of system was that, in order to reach a subscriber, one had to know his location since the handset would assume the local area code of the base station serving it.
In rare cases, additional devices were added by both participants to encrypt conversations (such as discussions of important politicians).
The B-Netz would eventually be superseded by the technically superior C-Netz, which was put into operation on May 1, 1985.