 The VT125 added an implementation of the byte-efficient Remote Graphic Instruction Set, ReGIS, which used custom ANSI codes to send the graphics commands to the terminal, rather than requiring the terminal to be set to a separate "graphics mode" like the VT105.The VT100 form factor left significant room in the case for expansion, and DEC used this to produce several all-in-one stand-alone minicomputer systems.The VT103 included a cardcage and 4×4 (8-slot) Q-Bus backplane, sufficient to configure a small LSI-11 system within the case, and supported an optional dual TU58 DECtape II block addressable cartridge tape drive which behaves like a very slow disk drive.