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. In February 1958 at the AIEE Winter General Meeting, Howard introduced the MITE (Miniaturized Integrated Telegraph Equipment) Model 103, a highly compact teleprinter, designed to compete in both commercial and military applications against much larger machines produced by Teletype Corporation. 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. The newly formed business was named the MITE Corporation, the acronym being repurposd as Miniature Industrial Technical Equipment to encompass Greist's preexisting products.

The MITE Model 104 was widely adopted by the U.S. military, and was developed into over a dozen similar teleprinters and teletypewriters with both system and component designations. The first military 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.

©2000-2017 The Vintage Technology Association. All rights reserved.