This figure shows SL3000 addressing, including the Base Drive Module (BDM) and expansion modules added to panels to the left and right of the BDM.
Base Module (BDM): Panel 12 (rear wall) and Panel 13 (front wall)
Drive Expansion Module (DEM) can be added to the left of the BDM, panels 10 (rear wall) and 11 (front wall)
Cartridge Expansion Modules (CEMs) can be added to the left or right of the BDM, in the following rear wall/front wall panel locations:
Left of BDM: Panels 8/9, 6/7, 4/5 and 2/3
Right of BDM: Panels 14/15, 16/17, 18/19, and 20/21
Access Expansion Modules (AEMs) can be added to panels 0/1 (panels on left end of library) or panels 22/23 (panels on right end of library)