NORBIT

In electronics, the NORBIT family of modules is a very early form (since 1960) of digital logic developed by Philips (and also provided through and Mullard) that uses modules containing discrete components to build logic function blocks in resistor–transistor logic (RTL) or diode–transistor logic (DTL) technology.
Overview.
The system was originally conceived as building blocks for solid-state hard-wired programmed logic controllers (the predecessors of programmable logic controllers (PLC)) to replace electro-mechanical relay logic in industrial control systems for process control and automation applications, similar to early Telefunken/AEG Logistat, Siemens Simatic, BBC Sigmatronic, ACEC Logacec or Estacord systems.
Each available logical function was recognizable by the color of its plastic container, black, blue, red, green, violet, etc. The most important circuit block contained a NOR gate (hence the name), but there were also blocks containing drivers, and a timer circuit similar to the later 555 timer IC.
The original "Norbit" modules of the YL 6000 series introduced in 1960 had potted single in-line packages with up to ten long flying leads arranged in two groups of up to five leads in a row. These modules were specified for frequencies of less than 1 kHz at ±24 V supply.
Also available in 1960 were so called "Combi-Element" modules in single-in line packages with ten evenly spaced stiff leads in a row (5.08 mm / 0.2-inch pitch) for mounting on a PCB. They were grouped in the 1-series (aka "100 kHz series") with ±6 V supply. The newer 10-series and 20-series had similarly sized packages, but came with an additional parallel row of nine staggered leads for a total of 19 leads. The 10-series uses germanium alloy transistors, whereas in the 20-series silicon planar transistors are used for a higher cut-off frequency of up to 1 MHz (vs. 30 kHz) and a higher allowed temperature range of +85 °C (vs. +55 °C).
In 1967, the Philips/Mullard NORBIT 2 aka Valvo NORBIT-S family of modules was introduced, first consisting of the 60-series for frequencies up to 10 kHz at a single supply voltage of 24 V, only. Later, the 61-series, containing thyristor trigger and control modules, was added. A 90-series became available in the mid-1970s as well. There were three basic types contained in a large (one by two inch-sized) 17 pins dual in-line package, with nine pins spaced 5.08 mm (0.2-inch) on one side and eight staggered pins on the other side.