QT2022/32 - Data Sheet: DS3051
7.1.4 Section Overhead
This layer is responsible for reliable transport of an STS-N frame across the physical medium. Its functions include
framing, scrambling and error monitoring.
Table 11: Section Overhead Definitions
Overhead
Octet
Description
Value (Bits 1...8)
Function
A1, A2
Framing
A1 - 11110110
A2 - 00101000
These bytes are allocated in each STS-1 for framing purposes. A1, A2
bytes are never scrambled.
J0
Section Trace
Varies
This byte is defined only for STS-1 of the STS-192c frame. It is used to
transmit one fixed byte so as to allow a receiving terminal to check its
connection to an intended transmitter. This byte is specified in the
Layer Management block. J0 byte is never scrambled.
Z0
B1
Section Growth
Section BIP-8
11001100
Varies
Unsupported, not required by IEEE 802.3 Clause 50.
This byte is used for the section error monitoring function. This is a bit-
interleaved parity 8 code using even parity. It is calculated over all bits
of the previous STS-192c frame after scrambling. When using the
TOH Serial interface, the inserted value of B1 represents an inversion
mask. An inserted value of all zeroes preserves the calculated B1
octet.
E1
F1
Orderwire
00000000
00000000
Unsupported, not required by IEEE 802.3 Clause 50.
Unsupported, not required by IEEE 802.3 Clause 50.
Section User
Channel
D1-D3
Section Data
Communication
channel (DCC)
All octets set to
00000000
Unsupported, not required by IEEE 802.3 Clause 50.
7.1.5 Test Pattern Generation
The QT2032 provides WIS compliant test pattern generation features. Please refer to Section 11.5, “WIS Test Fea-
tures (QT2032 only),” on page 102 for details.
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