Older UNIBUS PDP 11s can be upgraded two ways, either with a box-level up- - grade using the 11/ DECswitch 900FO box product or with an 11X84 cabinet-based system configuration. These upgrade options are described below. All 11/84 box-level upgrades are designed around the standard 2-Mbyte product variations and all include Field Service installation. 11/84-U1 11/84-P to A series module set upgrade includes 11/84 CPU, 1 Mbyte of memory, MDM, and MLM. 11/84-U2 11/84-P to A series module set upgrade includes 11/84 CPU, 2 Mbytes of memory, MDM, and MLM. 11/ DECswitch 900FO -UA 10.5-in box-level upgrade includes 11/84-BA with 2 Mbytes of memory, diagnostics, documentation, and Field Service installation. 120 V/60 Hz. 11/84-UB 10.5-in box-level upgrade includes 11/ DECswitch 900FO -BB with 2 Mbytes of memory, diagnostics, documentation, and Field Service installation. 240 V/50 Hz. 11X84-UA System Cabinet Level Upgrade includes 11X84-BA with 2 Mbytes of memory, diagnostics, documentation, and Field Service installation. 120 V/60 Hz. DECswitch 900FO-UB System Cabinet Level Upgrade includes 11X84-BB with 2 Mbytes of memory, diagnostics, documentation, and Field Service installation. 240 V/50 Hz.