DS3 Network Elements NE such as fiber optic terminals FOT or M13 multiplexers M13 that are cabled to the DSX-3 require a 75 ohm load to stabilize the output signal.. This 75 ohm load or
Trang 1DS3 Network Elements (NE) such as fiber optic terminals (FOT) or M13 multiplexers (M13) that are cabled to the DSX-3 require a 75 ohm load to stabilize the output signal This 75 ohm load
or "75 ohm termination" prevents the output from oscillating and affecting adjacent channels When a NE is cross-connected to another NE, the output of each NE is terminated by the input
of the other NE
When multiple NEs are installed, many are often unassigned for a period of time until working service is required Although unassigned, the NEs are powered up "Hot" in a standby mode, waiting to be turned up live as soon as a service order is issued
When DS3 NEs are powered up but not yet cross-connected or assigned to other NEs, a 75 ohm termination is placed at the DSX-3 This 75 ohm termination may be placed in a number of ways as illustrated by the following figures
The 75 ohm termination is also required when disconnecting two NEs from each other for testing or reconfiguration This termination is provided by a DS3 test set or a 75 ohm
termination plug at the DSX-3 OUT jack
DSX-3
75 ohm Circuit Termination
Trang 23/01 • 1209
Applications
DSX-3 and 75 ohm Termination Plug Schematics
IN IN
R2 R3
} PIN Jack
} Card Edge Conn LS
TL
OUT R2
OUT
MON
R1
OUT BNC/TNC
IN BNC/TNC X-CONN
-48V LG TL TL
BNC/TNC
R1 = 93.1 ohm 1/8W Resistor R2 = 75 ohm 1/8W Resistor R3 = 464 ohm 1/8W Resistor
DSX Rear Cross-Connect Schematic
MON
OUT BNC/TNC R2
R1 R3 OUT R2
Tracer Lamp PIN Jack IN
OUT X-CONN
R1 = 93.1 ohm 1/8W Resistor R2 = 75 ohm 1/8W Resistor R3 = 464 ohm 1/8W Resistor
Card Edge Connector
LS
DSX Front Cross-Connect Schematic
75 OHM RESISTOR
75 ohm Termination Plug Schematic
Trang 33/01 • 1209
Applications
75 ohm Termination Plug at DSX-3 OUT Jack
DSX-3
MON
OUT
IN
X-OUT
X-IN
75 OHM TERMINATION PLUG
NETWORK ELEMENT 1
(TX)
(RX)
DSX-3
(TX)
(RX)
NETWORK ELEMENT 2
X-OUT
X-IN
OUT OUT
IN IN
OUT OUT
IN IN
75 ohm Termination Provided by the Far-End DSX-3 IN Jack
DSX-3
MON
OUT
IN
X-OUT
X-IN
NETWORK ELEMENT 1
75 OHM TERMINATION
75 OHM TERMINATION
(TX)
(RX)
DSX-3
(TX)
(RX)
NETWORK ELEMENT 2
X-OUT
X-IN
OUT OUT
IN IN
OUT OUT
IN IN
MON
OUT
IN PLUG
NOTE: 75 OHM TERMINATION PROVIDED INTERNALLY BY JACK OPERATION
75 ohm Termination Plug or Terminating Connector
at the DSX-3 Cross-Connect OUT Terminal
DSX-3
MON
OUT
IN
X-OUT
X-IN
NETWORK ELEMENT 1
(TX)
(RX)
DSX-3
(TX)
(RX)
NETWORK ELEMENT 2
X-OUT
X-IN
OUT OUT
IN IN
OUT OUT
IN IN
MON
OUT
IN
75 OHM TERMINATION PLUG (FRONT CROSS-CONNECT)
75 OHM TERMINATING BNC OR TNC CONNECTOR (REAR CROSS-CONNECT)
Trang 4ADC Telecommunications, Inc., P.O Box 1101, Minneapolis, Minnesota USA 55440-1101
Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice At any time, you may verify product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents.
Web Site: www.adc.com
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Applications
75 ohm Termination Provided by the Far-End NE Equipment (Working Configuration)
DSX-3
MON
OUT
IN
X-OUT
X-IN
NETWORK ELEMENT 1
75 OHM TERMINATION
IN RECEIVER
(TX)
(RX)
DSX-3
(TX)
(RX)
NETWORK ELEMENT 2
X-OUT
X-IN
OUT OUT
IN IN
OUT OUT
IN IN
75 OHM TERMINATION
IN RECEIVER
MON
OUT
IN