Dial box

Lore & Background

A standard dial box has eight jog wheels mounted on a plate. The plate is set upright with the help of a stand and usually located next to the computer screen for convenient access. The connection to a computer is made via the serial port (RS-232). One of the fields of application for dial boxes was molecular graphics.

At least two different models of dial boxes were sold with the SGI brand. The DLS80-1022 (SGI part number 9980992) was made by Danaher controls, has 8 large dials and a single DE-9 connector which contains both the power and data pins. The connection to the computer serial port and the dial box power supply is made with a special DE-9 – DE-9, DIN-5 splitter cable. Essentially the same dial box was also sold as the Sun Microsystems DLS80-1012, part number 370-1223-01.

The Japanese made SGI SN-921 (type number 9780804) has somewhat smaller dials. It has a separate 5 V power supply connector in addition to the DE-9 serial connector, but it also needs a serial cable with a custom pinout.

Reader's Guide

Dial boxes were common input tools in the first years of interactive 3D graphics, serving as a dedicated peripheral for tasks such as adjusting rotation and torsion angles of 3D models. Their availability for SGI and Sun Microsystems workstations made them a standard accessory in early 3D graphics environments. The field of molecular graphics was one application where dial boxes were used. Currently, dial boxes have been replaced by standard computer mouse interaction techniques, marking a shift in how 3D manipulation is performed. The existence of at least two SGI-branded models—the Danaher-made DLS80-1022 and the Japanese-made SN-921—illustrates the variety in design, with differences in dial size, connector configuration, and power supply requirements. The DLS80-1022 used a single DE-9 connector with a splitter cable for power and data, while the SN-921 required a separate 5 V power connector and a custom serial cable pinout. The Sun Microsystems DLS80-1012 was essentially the same hardware as the SGI DLS80-1022, indicating cross-platform availability. These details reflect the technical diversity and specialized nature of dial boxes before their obsolescence.

Did You Know?

• The LINC computer had a set of 8 knobs forming a rudimentary built-in dial box.
• The SGI DLS80-1022 dial box was made by Danaher controls.
• The Sun Microsystems DLS80-1012 is essentially the same dial box as the SGI DLS80-1022.
• The SGI SN-921 dial box has a separate 5 V power supply connector.

Purpose and Function

A dial box served as a dedicated hardware peripheral designed to give users direct, tactile control over three-dimensional objects rendered on a computer display. Rather than relying on a two-dimensional pointing device, the operator could physically rotate small wheels to adjust rotation and torsion angles of a model in real time, making the manipulation of 3D geometry feel immediate and intuitive. During the formative years of interactive 3D graphics, when software interfaces were still maturing and mouse-driven workflows had not yet become universal, these boxes provided a natural way to explore spatial relationships. They were bundled alongside workstations from major vendors such as Silicon Graphics and Sun Microsystems, signaling that the industry recognized the need for specialized input hardware in professional 3D environments. The device essentially translated the operator's hand movements into precise angular adjustments, bridging the gap between a static screen and the dynamic, multi-axis world of three-dimensional modeling.

Physical Design and Connectivity

The typical dial box presented a compact, upright form factor: eight jog wheels arranged across a flat plate, which was propped vertically by a small stand. Operators would position the unit beside their monitor so that the wheels fell within easy reach of the dominant hand while the eyes remained on the screen. All communication with the host computer traveled through a serial port using the RS-232 standard, a connection method that was ubiquitous in workstation environments of that era. The physical layout was deliberately simple—no buttons, no levers, just the eight rotary controls—because the entire purpose of the device was to map one-to-one onto angular parameters in a 3D scene. The stand kept the plate at a comfortable working angle, and the proximity to the display meant that the operator could make fine adjustments without breaking visual contact with the model being manipulated. This ergonomic arrangement reflected a design philosophy in which the hardware existed purely to extend the user's sense of spatial control over on-screen geometry.

Manufacturer Lineup and Model Variants

Two distinct dial box designs carried the Silicon Graphics name, each with its own manufacturing pedigree and connector layout. The first, catalogued as the DLS80-1022 under SGI part number 9980992, was produced by Danaher Controls and featured eight generously sized dials. Its single DE-9 connector housed both power and data pins, requiring a special splitter cable with a DE-9-to-DE-9 and DIN-5 configuration to feed both the box's power supply and the serial data line to the computer. Sun Microsystems marketed an essentially identical unit under its own branding as the DLS80-1012, part number 370-1223-01, demonstrating the close hardware overlap between the two workstation rivals. The second SGI model, the SN-921 (type number 9780804), was manufactured in Japan and distinguished itself with somewhat smaller dials. It separated its power delivery from data by including a dedicated 5-volt power connector alongside the DE-9 serial port, though it still demanded a serial cable with a non-standard pinout to function correctly.

Applications, Decline, and Nostalgic Afterlife

Beyond general-purpose 3D modeling, dial boxes found a notable niche in molecular graphics, where researchers needed to rotate and twist complex molecular structures on screen with precision that a mouse could not easily provide. The tactile, multi-axis control of eight independent wheels made it straightforward to explore the conformational space of a molecule without juggling multiple software menus. However, as interactive 3D graphics matured and standard mouse-based interaction techniques became sufficiently capable, the dial box gradually disappeared from the market. It was never a consumer product; its audience was the professional workstation user, and when that audience migrated to more versatile input methods, the peripheral lost its raison d'être. Yet the device has not vanished entirely from the digital landscape. Community-maintained resources—including configuration guides for macOS, Xorg input drivers, Python scripts for reading dial values, and detailed cable pinout documentation—testify to a small but persistent circle of enthusiasts who still seek to revive these analog-feeling controllers in modern computing environments.

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