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(3) Pointer processing
The H1 and H2 bytes are extracted from the descrambled receive frame and the following processing is
performed:
<1> Extraction of pointer value
<2> Frequency justification operation (Positive frequency justification, Negative frequency justification)
<3> Monitoring of pointer synchronization status
1st H1 byte
1
2
3
4
N
N
N
N
NDF (4 bits)
H1 byte after second byte
1
0
0
1
NDF:
New Data Flags. These flags enable or disable changing of the pointer value.
• NDF Enable = Requests changing of the pointer value
If three bits or more of the four bits coincide with 1001 (1001, 1000, 1011, 1101, 0001)
• NDF Disable = Does not request changing of the pointer value
If three bits or more of the four bits coincide with 0110 (0010, 0110, 0100, 0111, 1110)
SS bit:
Indicate the type of SPE.
Pointer: Indicates the position of first byte J1 of POH and requests Frequency Justification (stuff
operation).
I (Increment bit):
D (Decrement bit): Requests Negative Justification operation.
Concatenation indication: Indicates concatenation.
48
CHAPTER 3 FUNCTIONAL OUTLINE
Figure 3-9. Format of Pointer
1st H2 byte
5
6
7
8
9 10 11 12 13 14 15 16
S
S
I
D
I
D
I
D
Pointer (10 bits)
SS
H2 byte after second byte
S
S
1
1
1
1
1
1
Concatenation indication
Requests Positive Justification operation.
PRELIMINARY
All H3 bytes
I
D
I
D
Negative stuff bytes
1
1
1
1
NEC confidential and Proprietary
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