Basic Principles of Serial Data Transmission
2.2 Transmission mode in Point-to-Point Communication
PtP coupling and configuration of CP 340
28 Manual, 04/2011, A5E00369892-03
2.2 Transmission mode in Point-to-Point Communication
Introduction
When data are transmitted, all communication partners must adhere to a fixed set of rules for
handling and implementing data traffic. The ISO has defined a 7-layer model, which is
recognized as the basis for a worldwide standardization of transmission protocols for
computer-to-computer communication.
ISO 7-Layer Reference Model for Data Transmission
All communication partners must adhere to a fixed set of rules for handling and implementing
data traffic. Such rules are called protocols.
Protocol
A protocol defines the following points:
● Operating mode
Half-duplex or full-duplex operation
● Initiative
Which communication partners can initiate the transmission and under what conditions
● Control characters
Which control characters are to be used for data transmission
● Character frame
Which character frames are to be used for data transmission.
● Data backup
The data backup procedure to be used
● Character delay time
The time period within which an incoming character must be received.
● Transmission speed
The baud rate in bits/s
Procedure
This is the specific process according to which the data is transmitted.