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O3-4D1L3 U2
1631, Issue 4, October 2009
3. FUNCTIONAL DESCRIPTION
Up to four DS1 circuits are combined into a single OC3 signal by using VT1.5 and STS-1
mapping; DS1 numbers 1, 2, 3, and 4 are mapped into STS-1 VT1.5 #1 positions 1, 2, 3,
and 4, respectively. The DS1 payload is not modified. Figure 3 shows a functional block
diagram.
A. OC3 Circuitry
The optical interface for the 155 Mbps data stream conforms to the basic SONET structure
defined in GR-253-CORE.
Figure 3. O3-4D1L3 Functional Block Diagram
Surge
Protection
Power
Converter
-
-48 VDC
Input
CPU
EEPROM
RS-232
Driver
DB9
LEDs
DIP Switch
OC3 Framer
VT1.5 Mapper
T1 Framer
OC3
LC
DS1
24-Pin
T1
LIU
Transformers
Surge
Protection
Frame Ground
Alarm
Relays
Instant
Default
Switch
