Installation4-53510-A2-GN32-70 July 1999Removing and Replacing a Model 3510 DSUTo remove and replace the DSU: Procedure1. Disconnect the power cord – first from the outlet,then from the connector at the rear of the DSU.2. Remove the D8W and DTE cables from the DSU.3. If the DSU is to be removed from service andreplaced, strap the replacement DSU the same asthe old DSU.If the DSU is defective and needs repair, recordthe defect on a tag and attach it to the DSU.Return the DSU, power cord, and network cord tothe company per instructions included in theEquipment Warranty and Support section ofChapter 1.4. If the DSU has been repaired, verify and changethe strap settings, as necessary.5. Continue with Steps 4 through 11 of theinstallation procedure.Replacement of the Model 3510 DSU is complete.Model 3511 DSUsThis section includes the installation procedures for theModel 3511 DSU, which is designed for installation in aCOMSPHERE 3000 Series Carrier (Figure 4-2). Theseprocedures assume that the carrier has been installedproperly and is operational.CAUTIONDischarge any static electricitythat may be present on yourbody by touching a properlygrounded object (e.g., coldwater pipe, frame ground, ordata cabinet). Do not handlethe circuit card unnecessarily.The initial installation procedure for the Model 3511DSU requires the installation of a rear connector plateonto the rear of the COMSPHERE 3000 Series Carrier.After the initial installation, the DSU can be installed andremoved from the front of the carrier without firstdisconnecting the DTE cables at the rear of the carrier.This section provides the initial installation procedure andthe procedure for subsequent installations/deinstallations.NOTEWhen modular circuit cards areinstalled with non-modular cardsin the same carrier, modularcircuit cards like the Model 3511DSU must be installed on the leftside of the carrier (seeFigure 4-3).