The Telequipment D83 is a 50 MHz scope. It is a larger-screen, upright version of the Telequipment D75.
The D85 takes two plug-ins that are also compatible with D75, D63 and DM63. Vertical plugins include the V4 dual trace amplifiers, the V3 single channel differential amplifier, the V1 single channel amplifier, and the V5 single channel amplifier with delay line (primarily intended for the DM63/D63 mainframes that have no built-in delay lines, whereas D75/D83 do). Timebase plugins include the S1 single timebase and S2 dual timebase.