THE FORGOTTEN PIONEER

The Problem with History

Computing history often credits the same familiar names: Turing, von Neumann, Shannon, Aiken. But what about the engineers who built the actual hardware that made early computers possible? What about the practical innovators who solved complex problems with electromechanical logic before Boolean algebra was even applied to computing?

James R. "Bud" Harrington is one such forgotten pioneer. Between 1927 and 1936, he designed and patented a fire alarm system so sophisticated that it essentially functioned as an electromechanical computer—complete with programmable read-only memory, time-division multiplexing, round-robin arbitration, and human-readable printed output. And he did all of this before Claude Shannon's 1937 thesis introduced Boolean algebra to electrical engineering.

The Timeline

The Technology

How It Worked

The Encoding Disc

At the heart of each station was an aluminum disc approximately 2 inches in diameter with roughly 60 precision teeth around its edge. The face of the disc had a non-conductive coating (likely anodized aluminum) that was selectively engraved away in specific patterns—rectangular slots and circular dots arranged in concentric tracks.

Beneath this disc were multiple contact pins positioned at different radii. As the disc rotated one tooth position at a time, different combinations of pins would make contact through the engraved areas. This created a multi-dimensional encoding matrix where each disc position could activate different combinations of contacts—essentially a mechanical ROM chip.

The Communication Protocol

When a station activated, it would begin stepping its disc forward, sending 120V DC pulses on the signal wire with each step. The timing between pulses encoded the transmitted digits:

• Short gap: Same digit continues (counting pulses: tick-tick-tick = "3")
• Long gap: Next digit begins
• Round separator: Complete code finished, may repeat

A code like "5-3-2-1" would be transmitted as: 5 pulses, long gap, 3 pulses, long gap, 2 pulses, long gap, 1 pulse, very long gap (round complete).

The Multiplexing Magic

Here's where it gets brilliant: At certain disc positions, contacts would open one side of the Class-A loop. At other positions, the opposite side would open. This created time slots where stations on different sides of the loop could transmit without interfering with each other.

When multiple stations activated simultaneously, they would interleave their codes round-by-round. Station A might send its first round while Station B waits, then B sends its first round while A sends its second round, and so on. The central panel would decode these interleaved pulse streams, tracking each station's state independently.

State Information

The system encoded alarm states through prefix digits and round counts:

• Normal/Reset: Base prefix (e.g., "5-3-2-1"), transmits 1 round, then stops
• Alarm/Set: Changed prefix (e.g., "6-3-2-1"), transmits 5 rounds or runs continuously
• Supervisory: Different prefixes for valve open, valve closed, etc.

The Computer Connection

In the 1940s, as WWII demanded precision electronics, Autocall manufactured thousands of relays for anti-aircraft fire control systems. This work honed their expertise in high-speed, reliable electromechanical switching—exactly the technology needed for early computers.

When Howard H. Aiken needed relays for his Harvard Mark II computer (completed 1947), he turned to Autocall. The company supplied what became known as "HHA relays"—miniature, high-speed relays bearing Howard H. Aiken's initials. These same relays were used in subsequent Harvard computers through the early 1950s.

Physical evidence remains: Relay frames at the Harvard computer museum still bear the label "Autocall, Shelby, Ohio." This is the tangible connection between Harrington's fire alarm innovations and the birth of modern computing.

Why This Matters

Computing history tends to focus on the theoretical pioneers—the mathematicians and logicians who developed the abstract concepts. But hardware pioneers like Harrington often go unrecognized, even though they solved equivalent problems from a practical engineering perspective.

Parallel Innovation

Time-division multiplexing has roots in 1850s telegraphy (Moses G. Farmer's 1853 patent, Émile Baudot's 1870s-1880s systems). But those were synchronized systems for telegraph signals. Harrington's implementation appears to have dynamic arbitration where stations control their own access—more sophisticated than simple fixed time slots.

Round-robin arbitration doesn't appear in computing literature until the 1990s-2000s for bus arbitration. Yet Harrington implemented a mechanical round-robin system in 1931 for resource sharing on a network medium. He may have independently invented this concept decades before it became formalized in computer science.

Pre-Boolean Computing

Shannon's 1937 thesis "A Symbolic Analysis of Relay and Switching Circuits" introduced Boolean algebra to electrical engineering and laid the foundation for digital logic design. But Harrington's patents from 1927-1936 show a fully functional computing system built without this theoretical framework. He used counter-based logic—stepping switches, sequence control, and mechanical state machines—to achieve computational tasks.

This demonstrates that multiple paths led to computing. The Boolean approach won because it scales better and is easier to miniaturize, but mechanical counter logic was viable and, in some ways, more intuitive for engineers of that era.

The Tragedy of Lost Knowledge

The Autocall-Howe system remained in production until the 1970s—over 40 years of continuous manufacturing. Systems were installed in:

• The Pentagon (original fire alarm system)
• Major airports worldwide
• Ford Motor Company plants globally
• Universities (MIT, major state institutions)
• Major manufacturers (GE, Union Carbide, Caterpillar, etc.)
• Government buildings and military installations

At least one system is reportedly still operational today. Yet by the time the internet emerged in the 1990s, most people who understood how these systems worked had passed away. The institutional knowledge died with them.

Harrington's name appears on thousands of engineering drawings in the Autocall archives, but he's virtually unknown in computing history. His connection to the Harvard computers is documented only on relay frames in museum storage, not in the computing history books.

A Life Beyond Fire Alarms

James R. "Bud" Harrington was also an established pilot who helped found Lahm Airport in Mansfield, Ohio, flying there as early as 1933. He organized Harrington Air Service and Harrington Aviation, later forming the Harrington Manufacturing Company.

This combination of aviation, electrical engineering, and electromechanical design suggests a mind that thought in systems—someone who understood timing, sequencing, reliability, and the critical importance of fail-safe operation. These were exactly the qualities needed for both aviation and the mission-critical fire alarm systems he designed.