Table Of Contents
Cisco ONS 15216 Dispersion Compensation Unit User Guide
The Dispersion Compensation Unit (DCU) is a complementary part of the Cisco ONS 15216 product family. The DCU can interoperate with the ONS 15454, ONS 155xx, and ONS 15600 products.
This user guide contains functional and physical descriptions of the DCU shelf assembly (chassis) and its Dispersion Compensation Modules, instructions for installing the DCU chassis into the rack-mounted ONS 15216 shelf, and instructions for installing modules into the DCU chassis.
The DCU consists of the chassis and two modules. The modules function in both bidirectional and wavelength division multiplexing (WDM) directions. Figure 1 shows the front view of the DCU chassis with two modules installed.
Figure 1 Cisco ONS 15216 DCU Shelf Assembly (Front View)
Figure 2 shows the front panel of a DCU module.
Figure 2 Cisco ONS 15216 Dispersion Compensation Module (Front View)
Module capacity is determined by the level of chromatic dispersion compensation (CDC) granularity. Table 1 describes the DCU module models available; they include seven C-band and six L-band models.
In optical networks, the DCU provides compensation for accumulated chromatic dispersion effect in line and terminal sites. It provides a flexible solution for accumulated chromatic dispersion without dropping and regeneratating the wavelengths on the link, a process that would otherwise be necessary when accumulated chromatic dispersion exceeds the maximum allowed dispersion tolerance.
To provide effective compensation, the DCU is designed to operate over the entire band from 1525 to 1565 nm.
Two modules can be installed in the DCU chassis, one for east-to-west traffic and the other for west-to-east traffic. Each DCU chassis mounts into a 1-RU, 19-inch rack. A module consists of a fiber spool, connectors, and a connector adapter for input and output. The connector adapter has a cover that provides protection from laser radiation. The cover also protects against dirt and dust, which can cause equipment failure.
The DCU chassis has no connectors, but the DCU modules have one LC/UPC connector adapter. Table 2 describes the input connection.
Table 2 Dispersion Compensation Module Input Connection
Input Connector Connection From Type
LC-UPC type connector
Table 3 describes the output connection.
Table 3 Dispersion Compensation Module Output Connections
Output Connector Connection To Type
LC-UPC type connector
This section provides optical, environmental, and mechanical specifications for the DCU.
Table 4 lists the operating wavelengths.
Table 4 Dispersion Compensation Module Operating Wavelengths
Effect Band Range (nm) Reference (nm)
Table 5 lists the environmental specifications for the DCU shelf assembly (chassis).
Table 5 DCU Chassis Environmental Specifications
-5° — 55°C (23° to 131°F)
95% maximum, non-condensing
Table 6 lists mechanical specifications for the DCU module.
Table 6 Dispersion Compensation Module Mechanical Specifications
41.1 mm H x 208.2 mm W x 204.9 mm D
(1.62 in. H x 8.20 in. W x 8.07 in. D)
Minimum: 2 kg (4.4 lb)
Maximum: 3.5 kg (7.7 lb)
Remove and Install the Dispersion Compensation Modules
This section contains information for the removal and installation of the DCU modules, DCU chassis, and grounding.
Remove the Dispersion Compensation Modules
Use the following procedure to remove a DCU module:
Step 1 Place your right-hand thumb on the thumb-block located in the middle of the module.
Step 2 Use your right-index finger to push the connector spring lock located on the right-side of the module.
Step 3 Disconnect the connection.
Step 4 Use the rectangular pull handle provided on the left center of the front panel to pull the module until the connector spring lock releases.
Step 5 Use both hands to remove the module from the DCU chassis.
Install the Dispersion Compensation Modules
Use the following procedure to install a DCU module:
Step 1 Use both hands to push the module all the way into the chassis until the connector spring lock on the right side of the module clicks into place.
Step 2 Open the cover on the connector adapter (the cover has a laser warning) and then connect the cable connector.
Remove and Install the Dispersion Compensation Unit Chassis
Warning This equipment must be grounded. Never defeat the ground conductor or operate the equipment in the absence of a suitably installed ground conductor. Contact the appropriate electrical inspection authority or an electrician if you are uncertain that suitable grounding is available. Statement 1024
Note When removing or installing the DCU chassis, you must connect the ground first and disconnect it last; see the "Remove and Install the Chassis Ground Strap" section for more information.
Remove the DCU Chassis
Use the following procedure to remove the DCU shelf assembly:
Step 1 Remove all DCU modules from the chassis ( "Removal and Installation of the Dispersion Compensation Modules" section on page 5).
Step 2 Disconnect the ground cables from the DCU chassis.
Step 3 Remove mounting screws from the mounting brackets and lift the DCU chassis out of the rack.
Install the DCU Chassis
Use the following procedure to install a DCU shelf asssembly:
Step 1 Position the DCU chassis in the rack to align the mounting brackets.
Step 2 Insert the mounting screws into the mounting brackets and tighten the screws.
Step 3 Connect the ground cables to the DCU chassis using the "Install the Chassis Ground Strap" procedure.
Remove and Install the Chassis Ground Strap
When installing or removing the DCU chassis, you must connect the ground first and disconnect it last.
Remove the Chassis Grounding
Use the following procedure to remove the chassis ground:
Step 1 To disconnect the ground strap from the DCU chassis, remove the lug screw and grounding lug.
Step 2 Disconnect the chassis ground strap from the office ground point or the rack ground point.
Step 3 Disconnect the chassis ground strap from the DCU chassis.
Install the Chassis Ground Strap
Use the following procedure to install the chassis ground strap:
Step 1 Connect the chassis ground strap to the DCU chassis.
Step 2 Terminate the chassis ground strap to either the office ground point or the rack ground point before applying power to the unit.
Step 3 Use the grounding lug to attach the ground strap to the chassis according to local site practice.
Fiber-Optic Connector Cleaning and Maintenance
Regular connector cleaning is required to maintain the performance of fiber-optic circuits. Before installing the fiber-optic cable, always perform the cleaning procedure for cable connectors described in the following section. Whenever possible, inspect each connector before making a connection.
Warning Invisible laser radiation may be emitted from disconnected fibers or connectors. Do not stare into beams or view directly with optical instruments. Statement 1051
Warning Ultimate disposal of this product should be handled according to all national laws and regulations. Statement 1040
Customer Supplied Cleaning Materials
The following cleaning materials are recommended but are not supplied with the DCU:
•Reagent grade ethyl alcohol in an alcohol dispenser
•Lint free laboratory wipes
•Clean, dry, oil-free, compressed air
When cleaning a paired cable connector (bulkhead mating adapter), always clean the mating adapter first. If the mating adapter is properly maintained, meaning it is used with clean, defect-free fiber connectors and capped when not in use, it should not require cleaning. However, if you suspect the adapter is dirty, clean it by blowing the adapter with clean, dry, oil-free compressed air. Always keep unused adapter ports and fiber connectors capped with a clean dust cap.
Clean Fiber-Optic Cable Connectors
Step 1 Remove the dust cap from the fiber connector.
Step 2 Wipe the connector tip with the pre-moistened alcohol wipe.
The design of the LC connector makes it difficult to clean the entire perimeter of the ferrule, because only a small portion close to the ferrule tip is accessible. Clean the tip of the ferrule and the entire accessible perimeter. Keep the fiber connector capped at all times when not in use.
Step 3 Blow dry using filtered air.
Step 4 Use an inspection microscope to inspect each fiber connector for dirt, cracks, or scratches. If the connector is not clean, repeat Step 1 through Step 3. If the connector shows damage (for example, scratches or pits across the fiber core), replace the fiber patch cord with a new one equipped with a defect-free connector.
Step 5 Insert the fiber connector into the applicable adapter or attach a dust cap to the fiber connector.
Note If you must replace a dust cap on a connector, first verify that the dust cap is clean. To clean the dust cap, wipe the outside of the cap using a dry, lint-free wipe and swab the inside of the dust cap using a Cletop stick swab (14100400).
Clean the Internal Fiber-Optic Cable Connectors
The connectors on the DCU modules are inside adapters and need special cleaning treatment because they are difficult to access. Use the following procedure to clean internal fiber-optic cable adapters:
Step 1 Remove the dust plug from the fiber adapter.
Step 2 Insert a Cletop stick swab (14100400) into the adapter opening and rotate the swab.
Step 3 Place dust plugs on the fiber adapters when not in use.
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