Technical data

Using the European V.24 standard as an example, this is a logical specification that is
specified by the physical layer. It only defines the task of the lines: control, data and pos-
sible transmission rates. Hence the V.24 standard is supplemented with an electronic
specification known as V.28, which is also a subset of the physical layer.
V.24 and V.28 have their counterpart in the American standard RS-232, which specifies
the physical as well as the electrical interface.
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22
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4
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6
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7
Trans-
mitter
Application
layer
Handles information for the application, secrecy and identification etc.
Responsible for code transformation, formatting, conversion and encryption.
Controls the data flow and buffering.
Handles point to point communication, and also checks that it is free from errors.
Handling addressing, paths, performance etc.
Control and monitoring of the data traffic.
Defines the electrical and mechanical interface.
Presentation
layer
Application layers
Network independent
layer
Interface
Session
layer
Transport
layer
Network
layer
Data link
layer
Physical
layer
Transference
media
Trans-
mitter
Description and function
B A C K