Telematics is the combination of informatics and telecommunication. It includes a total of services connected with the usage of informatics. The are accessible for the transmission of data by middle from networks.
Data-communication is the combination of data-processing and telecommunication. It includes the processing of data of program's running on computer-systems, and the communication over great distance where the information is transported by using of electrical-conductivity, radio-ways, light-signals, etc.. With data-communication is it possible to communicate over great distances from terminals connected on the communication network.
Figure 1 shows different possibilities for communication of great distance.
Character-sets (ASCII & EBCDIC), parallel/serial, method's of transmission (Asynchronically: all characters are directly and independently from eachother transmitted. It begins with a start-, and ends with a stop-bit. & Synchronically: The information-packet is transmitted in block.), simplex/half-duplex/full-duplex, and the speed from the data-transmission.
Is designed so that the actions of one user do not affect the network access of another user. No network is really accident-proof. Therefore, we must reduce the impact of a user's mistake on the other users, while knowing well that some accidents cannot be planned for. Design a network that a user cannot bring down by merely disconnecting his PC, or even by accidentally cutting a wire in his office.