Written by Accutron on 2017-05-21  

In 1953, engineer Bernard Howard of the Teleprinter Corporation began development of a mechanical teleprinter mechanism with a rotating print head. Howard's goal was to create a radically different high speed teleprinter mechanism with a minimum of high speed mechanical movements, which was not simply a scaled down (and consequently fragile) rendition of preexisting designs. In February 1958 at the AIEE Winter General Meeting, Howard introduced the highly compact MITE (Miniaturized Integrated Telegraph Equipment) Model 103 teleprinter, designed to compete in both commercial and military applications against much larger machines produced by Teletype Corporation and Kleinschmidt. In 1960, the MITE Model 104 revised teleprinter was selected for use by the U.S. Navy, prevailing over Teletype Corporation's much bulkier TT-242/UG lightweight teletypewriter. In 1961, Teleprinter Corporation merged with Greist Manufacturing Company, securing the production capabilities needed to meet large-scale military contracts. Established in 1871, Greist was once the world's leading manufacturer of sewing machine attachments. This newly formed business was named the MITE Corporation, the acronym being repurposd as Miniature Industrial Technical Equipment to encompass Greist's preexisting products.

Although the Model 104 experienced significant initial adoption by the U.S. Navy, early enthusiasm for the design was quickly tempered by mechanical failures and overheating problems. MITE's military contract soon fell into jeopardy, prompting the U.S. Navy to seek a replacement. Teletype Corporation responded with the relatively bulky AN/UGC-20 and AN/UGC-25, "miniaturized" KSR and RO versions of the Model 28 teletypewriter. MITE eventually corrected the problems found in early machines, but the revised design remained a temperamental device, known for its particularly noisy, high-strung operation and difficulty of repair.

In 1967, the MITE Corporation became the subject of a minor political scandal, when it was discovered that Senator Thomas J. Dodd (D-CT) had previously accepted a $2000 bribe from MITE president Robert J. Blinken in exchange for his support in obtaining a no-bid teleprinter contract. Although Dodd's efforts were unsuccessful, the MITE Corporation ultimately won the contract in competitive bidding, undercutting competitor Kleinschmidt by $50 per unit.

By the late 1960s, Model 104 teleprinters started showing up as military surplus, and were subsequently adopted by amateur RTTY operators in modest quantities. MITE teleprinters still see occasional amateur use, though they are vastly outnumbered by less brittle machines from Teletype Corporation and Kleinschmidt. After the Model 104, MITE introduced a number of subsequent mechanisms, including the Model 105 parallel input teleprinter, the Model 118-A and 119 subminiature teleprinters, and the 123P ASCII teleprinter, though none of these devices saw wide use.

The Model 104 was developed into over a dozen similar AN System teleprinters and teletypewriters with both system and component designations. The first models were the TT-298/UG RO teleprinter and the TT-299/UG KSR teletypewriter, introduced in 1960. Both of these machines were components of the AN/UGC-12 Teletypewriter Set, a fixed installation which also included a TT-187/UG signal distributor and a TT-192/UG paper tape reperforator. The AN/UGC-41 Teletypewriter Set pictured here is a standalone KSR teletypewriter introduced in 1966, equipped with a TT-532/UG Keyboard-Transmitter and a CY-6063/UG Non-Tactical Case. Other MITE machines include the AN/TGC-14, AN/TGC-15, AN/TGC-29, AN/UGC-38, AN/UGC-40, TT-264/AG, TT-297/UG, TT-318/UG, TT-394/UG and TT-395/UG. All of these machines share the same mechanism and basic form factor, differing only in secondary features.

The MITE teleprinter is almost entirely mechanical in operation, encoding and decoding 5-bit Baudot code via a magnetic selector which converts data into mechanical functions, actuating an elaborate arrangement of clutches, cams and linkages. The unusual MITE print head is an eight-sided, 64-character cylinder with two directions of motion, derived from a typewriter print mechanism invented by James Dundas White in 1903. In White's design, a cylindrical print head with rows and columns of characters rotates around a vertical axis to select a column, while moving up and down along its axis to select a row. A hammer then strikes the selected character from the opposite side of the paper. Although functionally similar to White's mechanism, the MITE print cylinder is oriented along a horizontal axis and has a vertical plane of rotation. As the print hammer advances incrementally to each successive character position, the print cylinder moves independently along a parallel rail, rotating to select the correct character row while advancing to one of eight column positions relative to the hammer. Three bits select the print cylinder's column position, while two bits select among four of the print cylinder's eight rows. As five bits is only sufficient to generate 32 different characters, a pulley carriage selects between two master row positions 180 degrees apart, determined by whether the machine is set to the Letters or Figures condition. The MITE mechanism is capable of operating at 60, 66, 75 or 100 words per minute, with a 72- or 76-character line. At 60 words per minute, the data throughput rate is 110ms per character, or 22ms per bit.

Technical Manual for Teleprinter Sets AN/UGC-38 & AN/UGC-40 & Teletyepwriter Set AN/UGC-41 (PDF)

MITE AN/UGC-41 Teletypewriter Set.

AN/UGC-41 teletypewriter removed from case.

AN/UGC-41 64-character print cylinder.

AN/UGC-41 teletypewriter, printer mainshaft clutch and cam assembly.

AN/UGC-41 teletypewriter, print cylinder horizontal drive pulley and range dial.

AN/UGC-41 teletypewriter, magnetic selector adjustment bank.

AN/UGC-41 teletypewriter, electronic module.

This article is part of the [Digital Computer Equipment] exhibit.

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