System Modules (originally known as System Building Blocks; the name was changed around 1961) are a DEC modular

digital logic A logic gate is an idealized or physical device implementing a Boolean function, a logical operation performed on one or more Binary number, binary inputs that produces a single binary output. Depending on the context, the term may refer to an id ...

family which preceded the later

FLIP CHIP Flip chip, also known as controlled collapse chip connection or its abbreviation, C4, is a method for interconnecting dies such as semiconductor devices, IC chips, integrated passive devices and microelectromechanical systems (MEMS), to externa ...

s."Digital Logic Handbook", pg. 56 They connect to the units they are plugged into via a set of 22 gold-plated discrete pins along one edge."System Modules", pg. vii They use

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

inverter circuits, with the transistors operating saturated, to avoid dependence on tight tolerances; they use -3V and 0V as logic levels. Intended for prototyping as well as production, they include design features intended to avoid damage. They are provided with design advice which includes loading rules and wiring instructions."System Modules", pg. 4.1-4.9 They were available in several compatible speed lines: * 4000-Series: the second series, nominally 500 KHz, but some 1 MHz"System Modules", pg. 6.1-6.40 * 1000-Series: the original series, nominally 5 MHz"System Modules", pg. 7.1-7.16 * 6000-Series: higher speeds, nominally 10 Mhz"System Modules", pg. 8.1-8.13 * 8000-Series: very high speeds, nominally 30MHz30 Megacycle Modules"
/ref> In addition, special modules were available for purposes such as

Input/Output In computing, input/output (I/O, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals ...

(I/O) converters (to standard internal voltages), bus drivers, lamp and solenoid drivers, A/D conversion, relays,

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...

drivers, etc."System Modules", pg. 9.1-9.60 Larger assemblies which are part of the same family provide core memory testing devices. There are also power supplies, mounting panels with slots for the modules, cabinets to hold groups of mounting panels, indicator light panels, etc."System Modules", pg. 10.1-10.35

References

;Citations ;Sources * * *

External links

DEC Building Block Logic manual from the Computer History Museum, dated September 1960Digital Logic Handbook, Third Edition, dated March 1961

New Module Accessories, dated February 196430 Megacycle Modules, dated September 1964System Modules, dated 1968
{{Digital Equipment Corporation DEC hardware *