Digi NS9215 - Manual (Page 417)

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S E R I A L C O N T R O L M O D U L E : H D L C
Data encoding
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between the opening and closing flags, except for the inserted zeroes, to the
receiver data buffer.
Last byte bit
pattern table
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D a t a e n c o d i n g
The HDLC module provides several types of data encoding:
Normal NRZ
NRZI
Biphase-Level (Manchester)
Biphase-Space (FM0)
Biphase-Mark (FM1)
Encoding
examples
This figure shows examples of the data encoding types.
In NRZI, Biphase-Space and Biphase-Mark, the signal level does not convey
information. The placement of the transitions determine the data.
In Biphase-Level, the polarity of the transmission determines the data.
Last byte bit pattern Valid data
bbbbbbb0 7
bbbbbb01 6
bbbbb011 5
bbbb0111 4
bbb01111 3
bb011111 2
b0111111 1