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Circuit Pack Descriptions
7-32 Issue 3 June 2001
Figure 7-11. BBF1/BBF1B DS1 Option Switches
DS1 Quick Reference Summary 7
Transmit Functions 7
Major transmit functions of the DS1 circuit pack are as follows:
â– Receives four AMI or B8ZS encoded DS1 signals from a DSX-1
â– Recovers DS1 clock and NRZ data from each DS1 signal
â– Synchronizes and maps each data signal to a VT1.5 synchronous payload
envelope (SPE)
â– Inserts VT path overhead
â– Multiplexes four VT1.5 SPEs to a byte-interleaved VT-G signal
â– Provides the VT-G signal to a MXRVO/STS1E circuit pack.
Receive Functions 7
Major receive functions of the DS1 circuit pack are as follows:
â– Receives a SONET VT-G clock and frame synchronizing signals from its
associated MXRVO/STS1E
â– Demultiplexes the VT-G into four VT1.5 signals
â– Terminates VT path and the embedded DS1 signal from each VT1.5 SPE
â– Desynchronizes the DS1 signals
â– Encodes each DS1 signal into either AMI or B8ZS format
â– Pre-equalizes (with LBO) each DS1 and provides them to a DSX-1 as
bipolar signals.
DS1LineCodeSettings
Line Code Format
(Note 2)
DIP Switch Settings (Note 1)
S1-4
(Port 1)
S1-5
(Port 2)
S1-6
(Port 3)
S1-7
(Port 4)
B8ZS OFFOFFOFFOFF
AMI ON ON ON ON
Notes:
1. Switch section 8 (S1-8) is unused and ignored by the system.
2. Line code is software overrideable.