Physical Layer
In asynchronous serial communication at the physical protocol layer, the data blocks are code words of a certain word length, for example octets (bytes) or ASCII characters, delimited by start bits and stop bits. A variable length space can be inserted between the code words. No bit synchronization signal is required. This is sometimes called character oriented communication. Examples are the RS-232C serial standard, and MNP2 and V.2 modems and older.
Read more about this topic: Asynchronous Communication
Famous quotes containing the words physical and/or layer:
“It takes a good deal of physical courage to ride a horse. This, however, I have. I get it at about forty cents a flask, and take it as required.”
—Stephen Leacock (1869–1944)
“This world is run by people who know how to do things. They know how things work. They are equipped. Up there, there’s a layer of people who run everything. But we—we’re just peasants. We don’t understand what’s going on, and we can’t do anything.”
—Doris Lessing (b. 1919)