city call
Cityruf is a paging service that has been in operation since 1989 and operates in the 465 MHz range. Cityruf was restructured into Qbic in 1999. It supports call classes 0, 1 and 2. Incall class 0, messages are displayed acoustically or visually, in call class 1, numeric (N), 15 digits and some special characters can be displayed, and in call class 2, texts with up to 80 alphanumeric characters. Calls can be activated via the telephone network, ISDN, mobile communications networks, and the T-Online and Telebox-X.400value-added services. The transmission speed depends on the frequency band and is 512 baud or 1200 baud.
The network structure of the Cityruf network includes the radio exchange, which realizes access to the public telephone network, as well as connection to the paging concentrator. Up to 30 paging concentrators can be connected to one paging exchange. Each of these paging concentrators manages several paging transmitting stations, comparable to the base station in GSM networks, and passes the signals to these stations. The paging transmitters operate with frequency shift ke ying with an output power of 50 W to 100 W. They receive the signal from the paging concentrator, convert it to the 450 MHz frequency range, amplify and filter it, and radiate it through the antenna. Paging receivers are very small and divided into paging classes. They can display tone-only, numeric and alphanumeric.
The features to choose from are the single call, the group call, the collective call, the destination call and the info call. In the case of the individual call, the radio call is transmitted exclusively in registered call zones. With the group call, the call is received by several receivers with the same address. The group call is a sequential individual call in which the individual addresses receive the radio message one after the other. With the destination call, the sender of a radio call must specify the call zone, since no call zones are assigned to the receiver during registration. And with info call, a value-added service, the receiver can receive certain information, such as business or weather news on the radio receiver.
The European component "Cityruf International" networks the national Cityruf with Alphapage (France), Teledrin (Italy), and Euromessage (England, Switzerland).