Alcatel-Lucent 1643 AMS Applications And Planning Manual page 273

An SDH overview
SDH STM-1 frame
Section overhead (SOH)
The first nine bytes of each row with exception of the fourth row are part of the SOH
(Section OverHead). The first nine byte of the fourth row contain the AU pointer (AU
= Administrative Unit).
STM-1 payload
Columns 10 through 270 (the remainder of the frame), are reserved for payload
signals.
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365-312-801R7.2
Issue 3, May 2007
Alcatel-Lucent - Proprietary
See notice on first page
SDH signal hierarchy
A-5