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Licon and Cortron (ITW)

United States



Cortron was created as a spin-off from Licon, as a dedicated keyboard manufacturer, as noted in the Series 555 advertisements in Computer Design magazine in September and December 1976 (see Documentation below). Cortron was later sold to Amkey, who went on to merge with Cortron, with the new company taking Cortron’s name.

Details about the new Amkey-owned Cortron and present-day Cortron can be found on the Amkey and Cortron page.


This page is at present an overview of ITW Licon and ITW Cortron keyboards, prior to Amkey’s acquisition of Cortron. Details on the product families is fairly scarce still.

The general pattern of the part numbers seems to be as follows:

Keyboard part PCB part Possible series Switch type
55-□xxxxx 80-55xxxx Series 550? Ferrite core, original design
55-5xxxxx 80-55xxxx Series 555 Ferrite core, low profile
45-5xxxxx 80-45xxxx CP-4550 Capacitive leaf
35-5xxxxx 80-35xxxx Series III SS3
25-□xxxxx 80-25xxxx Series FC2500? Ferrite core, DIN-compliant low-profile
25-5xxxxx 80-25xxxx Series FC-2550? Ferrite core, DIN-compliant low-profile

The specific breakdown between series is only a guess at this time, as there are just too few examples of anything except Series 555. In particular, no linear DIN-compliant ferrite core types have ever been found, and most DIN-compliant ferrite keyboards are not properly documented. No keyboards from before Series 555 have been documented; one example was listed on eBay with photos that did not clearly show the switches, but that listing is now long gone.

Note that the third and fourth digits of the PCB part number correspond to the first two digits of the keyboard part number.


The table below provides an overview of relevant Illinois Tool Works patents, taken out on behalf of Licon and Cortron for keyboards. Several patents (thus marked) all derive their priority from application US14490271A (filed in May 1971), themselves filed in 1972, 1974 and 1981, with one of the patents filed in 1974 not being granted until 1985.

“Series 555” is used to indicate switches found in Series 555 keyboards, until we know the series identity of “Style A”, as it may not be part of Series 54.

Patent Title Filed Published Product
US 3638221 Solid-state keyboard 1969-11-24 1972-01-25 Wired inductive encoding for Series 550
US 3638222 Flux gate switch 1969-11-24 1972-01-25 Wired inductive encoding for Series 550
US 3612241 Keyboard switch construction 1970-03-30 1971-10-12 Series 550 keyswitch
US 3698531 Solid state switch 1970-10-26 1972-10-17 Sextuple-magnet rollover-capable ferrite core switch; possible variant of Series 550
US 3691333 Alternate action mechanism 1971-03-19 1972-09-12 Series 550 alternate action mechanism
US 3714611 Solid state switch construction 1971-11-18 1973-01-30 Low-profile version of the original Series 550 design
GB 1380282 Keyboards 1972-05-17 1975-01-08 Priority to US14490271A, 1971-05-19, seemingly unpublished
US 3824362 Alternate action switch mechanism 1973-05-23 1974-07-16 Alternate action switch (e.g. Series 54)
US 3882295 Tactile feedback switch mechanism 1973-10-04 1975-05-06 Tactile feedback mechanism (e.g. Series 54)
US 4517553 N-Key rollover keyboard 1974-04-04 1985-05-14 Priority to US14490271A, 1971-05-19, seemingly unpublished
US 3902032 Electrical switch with improved contact structure 1974-06-07 1975-08-26 Mechanical derivative of Series 555 switches (this patent references Hi-Tek’s patent filed two years earlier)
US 3918051 N-key rollover keyboard 1974-06-10 1975-11-04 Priority to US14490271A, 1971-05-19, seemingly unpublished
US 4099176 Magnetic key switch having a removable support assembly 1974-11-20 1978-07-04 Series 555 switches (priority date 1974-05-30)
US 3978474 Keyboard with n-key lockout and two-key rollover protection 1975-07-15 1976-08-31
US 4028696 Double depression magnetic keyswitch 1976-01-26 1977-06-07 Series 54 double action switch
US 4017850 Magnetic keyswitch with two-piece support assembly 1976-02-02 1977-04-12 Revised Series 54 ferrite core assembly, made from two identical halves
US 4071719 Keyboard switch assembly having actuator interlocking keyboard shift and shift lock and release mechanism 1976-07-22 1978-01-31 Mechanical shift lock for Series 54
US 4227163 Electrical keyswitch 1979-03-05 1980-10-07 SS3 ferrite core and the corresponding unidentified mechanical switches
US 4263582 Keyboard with an externally programmable repeat rate and repeat delay rate counter 1979-08-24 1981-04-21
US 4295012 Secretarial shift mechanism for an electric keyboard 1980-02-04 1981-10-13 Mechanical shift lock for SS3 ferrite core and the corresponding unidentified mechanical switches
US 4390866 Keyboard with electronic hysteresis 1981-02-19 1983-06-28 Priority to US14490271A, 1971-05-19, seemingly unpublished
US 4352144 Capacitive keyswitch with overtravel plunger mechanism 1981-01-21 1982-09-28 CP-4550 capacitive keyboards
US 4480937 Breakaway leafspring actuated keyswitch apparatus 1982-08-30 1984-11-06 Unknown snap-action leaf spring mechanical type
US 4453063 Keyswitch configuration with torque rod holder 1983-08-03 1984-06-05 FC-2550/FC2500 integrated stabiliser clip
US 4535210 Keyswitch stabilizing device 1984-04-18 1985-08-13 FC-2550/FC2500 keycap stabilisation
US 4704601 Keyboard data entry system with hysteresis 1985-06-27 1987-11-03

US patent 4453063 says of the keycap mount, “This sleeve is not illustrated since the key cap and the switch actuator are old.” Likewise, of the switch implementation, “Various details of structure of the switch are not shown since they are old and are of no consequence to the present invention.” As such, it appears that the DIN-compliant design (FC-2550 and/or FC2500) were not patented, with the means of reducing the size of the switch not deemed to fall outside of the existing patents.

Switch types

Ferrite core

These are solid state switches which are sensed by controlling whether or not current will pass inductively from one wire to another through a ferrite core. They have been referred to as “magnetic valve” switches within the keyboard enthusiast community, but in advertisements from Licon and ITW, they are described as “ferrite core”. Here, the magnet in the plunger saturates the ferrite core—suppressing the inductance—and when the plunger is depressed, the inductance is restored and the key will be detected. These solid state switches are around the same age as Micro Switch SW, which is a Hall effect solid state keyboard series.

Cortron noted of these keyboards, “The Ferrite Core style switches were sensitive to PCB layout, grounding, and most importantly stray EMI or ESD. The way the wires or leads went up thru the core acted like antenna receivers or emitters, depending on inputs.”

The following diagram depicts two of ITW’s implementations; the original version used individual wires passed through the cores, before they moved onto discrete assemblies soldered to a printed circuit board.

In most cases, the older switches are all Micro Switch mount. The DIN-compliant types use a German-style snap on mount, although compatibility with German switches is not confirmed. However, HP 264XX Data Terminal keyboards use switches that appear to be designed for compatibility with Cherry M6 switches:

The technical literature for the simplified keyboard from this HP series—from August 1976—gives only HP part numbers for the “LICON” switches used.

Ferrite core keyboards are normally linear. Keyboards made for the Trendata 4000 use a patented click feedback system, found in US patent 3882295 filed in October 1973. The patent is titled “Tactile feedback switch mechanism” but it does specifically generate both audible and tactile feedback. The tactile feedback was added to simulate the feel and sound of “mechanical” switches, to avoid operator error arising from a lack of feedback that a key actuated. John “Jack” Spindler, who was part of the team at some point, noted: “They were also made to feel and sound like a Selectric typewriter keys. They felt that secretary would find transition easier.” This would not be the only product line designed to approximate the feel of an IBM Selectric.

As noted by Jack Spindler, the switch had the advantages of having no contact bounce and low manufacturing costs (with no intricate metalwork and very few parts per switch). The Deskthority forum topic Scanning a cortron Diablo keyboard demonstrates some of the complexity dealing with scanning the matrix, likely due to the very weak signals inherent in the design.

The inductive sensing created for their keyboards was later adopted by Licon for additional purposes. The article Transducers based on switch designs (Electronics vol. 48 no. 7, 3rd April 1975, pp. 39–40) describes the adaptation of the inductive keyswitch sensing for automotive sensing, in particular speed detection for anti-skid control. Later that year, the article Ferrite pot has no contact wear (Electronics vol. 48 no. 21, 15th October 1975, p. 34) describes a further adaptation to provide a contactless potentiometer, also intended for the automotive industry.

Capacitive leaf

This is a capacitive keyboard that uses a leaf spring under each key instead of a foam pad with foil attached. The design is very similar to Digitran Golden Touch switches. The examples below have a series of patents on the label but the switch patents thereon are for ferrite core switches.


At least two switch designs were also patented with mechanical contacts. So far, no ITW mechanical keyboards have been discovered.


It appears that keyboards and switches were assigned separate series. Switch series names were likely all two-digit numbers, while keyboard series used three and four digits. The mechanical switches may have had alphanumeric codes, with Cortron suggesting something like “E3” or “E4”.

Series 550

Series 550 is presently the oldest known keyboard series. These keyboards, introduced around 1969, used threaded-wire switches. The oldest description of this series is from October 1969, and the patent for the encoding technique was filed in November that year. The oldest (and only) known depiction of the original switches is from an advertisement in Modern Data in December 1970. The rated lifetime was 25 million cycles. These switches do not use a PCB. Instead, a ferrite core is fitted to each switch, and one or more windings are fed through the cores, one per output bit. Unlike later designs, which only ever used a single wire for each winding, these switches were illustrated as using multiple wires for the windings.

Licon advertised a wired inductive encoding system where the encoding was defined by which sense wires passed through each ferrite core. This principle is covered under US patent 3638221 “Solid-state keyboard” filed in November 1969. The general principle is illustrated in the diagram below. The diagram does not cover the saturation of the induction cores; only the encoding technique is depicted. The advertisement in Modern Data shows many wires passing through the core, in accordance with the written description of the encoding used. The ferrite core wiring was automated in the factory.

In a letter to the editor, published in Electronics magazine on the 1st of March 1971 (page 8), John Pfeiffer from Licon offered a correction to a claim made in the In key with computers panel of the article Capacitive keys, simpler circuits add up to reliable keyboard from the 7th of December 1970 issue, where Licon’s keyboards were said to use TTL encoding. Licon countered:

… the Licon keyboard technology was misrepresented. One of its most important features is encoding at the switch, which allows the customer to choose standard or custom encoding formats without special tooling and eliminates the need for a diode matrix or MOS chip.

Within a year or so, the switch size was drastically reduced, as shown in a fresh patent. Keyboard 55-000084, manufactured for Sanders Data Systems, uses wired inductive low-profile switches exactly as per US patent 3714611 “Solid state switch construction”, indicating that the low-profile keyboards remained Series 550, although this is not verified by any literature. A 1971 advertisement in Electronic Design describes them, but does not name the series as the previous advertisement did.

Super Switch

Licon’s advertisement in Electronic Engineers Master 1973–74 Section 2000 is for an ASR33 keyboard with “Super Switch” ferrite core switches. From the top of the mounting plate to the bottom of the PCB, the height is shown to be 0.66″; this is effectively the distance for a Series 555 keyboard, suggesting that “Super Switch” could denote a switch series used in Series 555 keyboards.

However, a Super Switch keyboard was previously advertised in the Electronic Engineer in December 1972, with a switch design that does not match any patent or known switch type. Only the top of the switch can be seen (not including the plunger), making indentification difficult. These switches are also soldered to the PCB.

Keyboard 55-100007 from 1971 was most likely a Super Switch keyboard, with the implication that Super Switch keyboards were Series 551. The switches appear to be visually identical from above to the low-profile Series 550 switches, while the “Style A” switches used with Series 555 are a little different: the notches used to access the plate retention prongs are covered over in Series 555 keyboards, and the switches are a different design below the plate.

Series 555

Series 555 keyboards use low-profile ferrite core switches. These switches are specifically designed to be soldered to the PCB, although this change appears to pre-date Series 555. Patents for switches used in Series 555 date back to 1973, and the oldest advertisement discovered to date for Series 555 is from Computerworld, December 1972. A later Series 555 advertisement from Computer Design in September 1976 shows that both of the switch styles depicted in US patent 3902032 “Magnetic key switch having a removable support assembly” are used in the same keyboard series.

Although these keyboards are covered by a number of patents, most of these keyboards are marked as being covered by US patent 3035253, filed by George C Devol on magnetic storage.

This series includes a double-action switch that uses two ferrite cores. These switches are much taller than the standard momentary types, and while one could be forgiven for thinking that they belong to Series 550, they were patented after the standard Series 555 switches. These double-action switches can be found alongside standard-height momentary switches in the HP 9845 workstation keyboard.

Series 555 secretarial shift can be seen in the Xerox X998 keyboard.

Style A

This style of switch is rare. This design is so far only known from a Univac Uniscope 100 keyboard and for some of the alternate action switches in HP’s 9845B/C keyboard and 2645 keyboard. Style A switches keep the shell and the ferrite core assembly separate: removing the shell leaves the ferrite core assembly behind on the PCB. The design of the switch above the mounting plate is only marginally altered from previous switch designs.

The 1976 and 1981 service manuals for the HP 2645 give us (via NSN information) Cortron part numbers 54-0013 and 54-0202, suggesting that “Style A” switches are indeed part of Series 54, although stronger confirmation is still required.

Style B

This is the standard form of switch used in Series 555 keyboards, which is widely encountered, with examples ranging from the mid-1970s to the mid-1980s. These switches appear to be Series 54 Superswitch II; it is not known whether Style A also falls under Series 54. These switches have the ferrite core assembly snapped tightly into the switch shell.

Series 54

View full-size image
Series 54 alternate action, Cherry mount

Series 54 “solid-state” keyswitches got a brief mention in Computerworld, 31st of May 1976. This series was further mentioned in the NCC 1976 booth announcement for Licon, which refers to “series 54 Superswitch II standard, tactile, alternate action, double depression, incandescent, and LED keyswitches.” These switches are not depicted. It’s curious that the term “SS3” is later used for Series III switches; possibly those are “Superswitch 3” not “solid state 3”.

Indications are that these switches are the “Style B” type in the Series 555 keyboards. The paper The Licon Wheel Velocity Sensor—An Application of Ferrite Core Technology (Edward F Sidor and Rand J Eikelberger, Licon, 1976) appears to depict such a switch and makes reference to Licon Product Bulletin No. 05503 “Series 54 Superswitch II Keyswitch”, ITW Licon Application Note No. 05504 “Series "54" Keyboard Switch” and ITW Licon Technical Memorandum No. 230. “Technical Data, S.S. II, 0.180 Inch Travel, Single Sense, Non latching.”

A number of ITW parts beginning with “54-” are known. Some relate to keyboard switches, and some were located only via NSN information:

Part no. Type Customer part NSN Used in
54-0006-1-RED 5930-01-329-7836
Momentary; mount not observed HP 3101-1899 5930-01-049-8288 HP 264X (1976 service manual)
54-0013 Alternate action; mount not observed HP 3101-1900 5930-01-050-0561 HP 264X (1976 service manual)
54-0072 5930-01-040-8747
54-0073 5930-01-058-5024
54-0202 Alternate action; appears to be Cherry 12 mm mount HP 3101-2136 5930-01-095-0443 HP 264X (1981 service manual)
54-0203 Momentary; appears to be Cherry 12 mm mount HP 3101-2137 5930-01-095-0444 HP 264X (1981 service manual)
54-0440 5930-01-260-6460
54-0441 5930-01-244-7388

Series 56

Series 56 appears to be the keycaps that went with Licon Series 550 keyboards, based on a leaflet included with sample parts that may date to 1976. These are double-shot moulded keycaps, with the material given as “SAN copolymer”, denoting styrene-acrylonitrile resin. The slot in the keycap that accepts the plunger is shown to be 0.030±002″ wide and 0.250±0.002″ front-to-back, with a vertical depth of 0.340″ minimum. The keycaps are 0.716″ square and 0.477″ tall.

It would appear that Licon offered these keycaps for sale separately.


CP-4550 is a metal leaf capacitive system. The original design is covered by US patent 4352144 “Capacitive keyswitch with overtravel plunger mechanism”, filed in January 1981. The switch as illustrated in advertisements in Computer Design magazine in April and May 1981 exhibits a notable difference from the patent: the capacitive leaf has a tongue portion for the plunger to engage. This is effectively the same design as Digitran’s Golden Touch capacitive keyboards, that Cortron appear to have copied.

Cortron CP-4550 is mentioned briefly in Interface Age, August 1981 on pages 132 and 134, and is said to use the “CP-4550 keyswitch”. This switch is said to give an “exceptional, true linear feel” and is “environmentally superior to foam pad design approaches”. The rated lifetime is in excess of 100 million cycles.

The Recent Microsystems Announcements from Computer magazine, June 1981 cites this model as being a “Solid-state, capacitance unit”, with a unit price of $45 in volume quantity ($127 in June 2019). The $45 price also appears in the Computer Design magazine advertisements.

As with many other capacitive designs, CP-4550 keyboards have an external return spring visible under the keycap. This spring is however held captive by the plunger and will not be misplaced after removing a keycap. As with Series 555, the keycap mount appears to be Micro Switch.

All CP-4550 keyboards observed to date appear to have Comptec SA family keycaps.

Series III

Series III was advertised in Computer Design in July 1978 (and in later issues), with further details given in a written advertisement in August. Series III keyboards use SS3 ferrite core switches. The patent for the SS3 switches was not filed for nearly a year afterwards.

The only identifying marks of these keyboards is that the internal part numbers take the form 35-5xxxxx. As with Series 555 keyboards, these keyboards are also marked with US patent 3035253.


View full-size image
SS3 stabiliser dummy module

SS3 is a ferrite core keyswitch. “SS3” is likely to denote “Superswitch III”, that is, the third generation of self-contained ferrite core keyswitch. The design of the SS3 switch is not depicted in any known Cortron advertisements; instead, it can be seen in Celanese advertisements for two of the resins used for the switches: Celanex 2012 polyester resin for the base, and Celcon acetal copolymer resin for what appears to be the top cover.

The full-page Series III advertisements describe SS3 as follows:

Like its proven and successful predecessor, the SS3 keyswitch is mechanically simple and contactless. The SS3 is designed with fewer parts, lower profile and exceptional feel while maintaining excellent resistance to environmental factors. This combined with a 100 million cycle life test rating offers unsurpassed cost efficiency.

The shorter Series III advertisement notes:

ss3 keyswitches are contactless, with a low profile–0.5″ (1.27 cm) from mounting plate to keyboard bottom. Switch travel is a full 0.150″ (3.81 cm). Life test rating is 100M cycles.

Compared to the earlier Series 54, the keystem on the plunger seems to sit a fraction of a millimetre higher: SS3 does not seem to offer a keyboard that is overall any smaller that its predecessor. The distance from the PCB to the top of the mounting plate is however reduced by around 4.1 mm, from around 14.35 to 10.25 mm, and the plunger shaft appears to be specially reduced to allow the keycap to move down over it. The distance from the bottom of the mounting plate to the bottom of the terminals would be around 12.5 mm, which is the only measurement that would fit the advertised description. The term “keyboard bottom” may refer to an unenclosed keyboard module; it certainly could not describe an enclosed keyboard with the switches in question. Indeed, SS3 does seem a little tall considering the era, and seemingly unnecessarily so.

The claim of “fewer parts” is also a stretch. The Series 54 housing was a single piece, but the ferrite core assembly used a two-part snap-together enclosure. SS3 does away with the separate enclosure, but instead requires a cover to secure the ferrite core and windings, thus saving all of one part per switch. It’s not clear what precisely SS3 offers over Series 54. True low profile would follow in a few years in the form of the FC-2550/FC2500 DIN-compliant keyboards.

The earliest known advertisement for Series III is from July 1978. The patent for the switches, US patent 4227163 “Electrical keyswitch”—was not filed until March 1979. The Celanese advertisement depicting the switches would not appear until a year after the keyboards were advertised, in August 1979.

Options for SS3 switches include upright versus angled keystems, center illumination, dummy switches for wide key stabilisation, and multiple key weights.

The patent also covers a mechanical switch type that appears to share the same housing as the ferrite core type. Thus far, there has been no sign of the mechanical type.

Series FC-2550

Series FC-2550 is a DIN-compliant ferrite core design, advertised in 1981. These too are advertised with a 100 million cycle lifetime. FC-2550 switches are stated to have “true linear feel”.

Series FC2500

In Computerworld, 28th March 1983, Illinois Tool Works advertised Series FC2500 keyboards. These are described as “low-profile” and offered linear and tactile options. In Computerworld, 2nd July 1984 it is also noted that these keyboards were reported to meet a 30 mm height requirement. Series FC2500 is a candidate for the low-profile type that was later manufactured by Devlin in the UK, as currently there are no indications of FC-2550 being tactile. In neither case were any illustrations provided. An illustration of a switch is shown in Computer Design in May 1983 (see Documentation below), which is a good match for the 25-50xxxx keyboards.

The article La Tastiera in the Italian magazine Selezione di elettronica e microcomputer from June 1985 contains the following description of Series FC2500 on page 59:

Tastiera ITW Cortron con feedback sia tattile che visivo. Il modello FC2500 emette un suono simile a quello di un grillo quando viene premuto un tasto. Essa adotta la tecnologia a ferrite; il feedback tattile è fornito da interruttori a cupola.

This translates to:

ITW Cortron keyboard with both tactile and visual feedback. The FC2500 model emits a sound similar to a cricket when a key is pressed. It adopts ferrite technology; tactile feedback is provided by dome switches.

Computer Weekly (supplement) 5th of January 1984 announced the launch of an unspecified series of Cortron ferrite core keyboards, noting:

The low profile keyswitch measures 17.1 mm high with keytop, 21.9 mm, and has a full travel of 4mm. Keyswitches can be provided with linear or tactile feel.

It seems strange that FC-2550 was seemingly advertised before FC2500. Because so few ITW DIN-compliant keyboards have been properly documented, there is no way at present to determine whether FC2500 and FC-2550 use different part number prefixes.


“CP6500” is mentioned briefly in an article in Electronic Design magazine from 1985 (Alphanumeric keyboards, Mike Mullin, Electronic Design 33, 21st November 1985):

Plate-capacitive keyboards are very similar to the pad-capacitive types, except that a movable plate is mounted directly to the key top, with no pad in between. When the key is pressed, the plate approaches but does not touch the fixed plate. This switching arrangement is used by Illinois Tool Works Inc.’s ITW Cortron Division (Elmhurst, Ill.) in its CP4500 and CP6500 conventional and ergonomically designed keyboards.

One might assume that “CP4500” is the same as CP-4550, but this is not proven. CP6500 has yet to be discovered.


The following is a list of known Licon and Cortron keyboard models with both the switch type and part numbers known, arranged in date order:

Part number PCB number Manufacturer Switches Serial Date Notes Reference
55-100007 80-550461 Licon Ferrite core, PCB-soldered 7131 Most likely an original Super Switch keyboard eBay
55-000084 80-550646 REV B Licon Low-profile threaded ferrite core 46974764 7216 From an unidentified Sanders Data Systems device eBay
55-500081 80-551178 REV.B 4 Licon Series 54 tactile 025470 7514 Trendata 4000 keyboard Deskthority
55-500003 80-550782 REV G Licon Series 555 style A 005315 7585 Univac Uniscope 100 keyboard Deskthority
55-500081 80-551178 REV.D Licon Series 54 tactile 000933 7605 Trendata 4000 keyboard Deskthority
55-500081 80-551178 REV.D Licon Series 54 tactile 51439 7610 Trendata 4000 keyboard Deskthority
55-500140 80-550932 REV F Licon Series 54 59710 7621 Unidentified keyboard eBay
55-500161 80-551093 REV. J Cortron Series 54 293869 7934 Raytheon model 6101-04 Deskthority
55-500056 80-551101 REV D Cortron Series 54 346831 8004 Unspecified Raytheon model Deskthority
55-500135 80-551478 REV. B Cortron (Licon PCB) Series 54 367693 8012 Double-shot Japanese keycaps Flickr
55-500539 80-551879 Cortron Series 54 370322 8016 Xerox X998; part of the case is from 1982 Flickr
55-500219 80-551655 REV.B Cortron Series 54 406859 8030 Unknown origin imgur.com
35-500059 80-350072 REV. B Cortron SS3 455684 ~1980 Unidentified Univac keyboard Deskthority
55-500219 80-551655 Cortron Series 54 8107 Unknown origin eBay
35-500095 80-350128 REV. A Cortron SS3 526148 8133 Unidentified Univac keyboard Flickr
? ? ? CP-4550 ? ? Xerox 860 IPS CAT-less keyboard eBay
45-500008 80-450025 Cortron CP-4550 1007817 8311 Xerox 820-II keyboard (Xerox part 110S80564) deskthority
45-500008 ? Cortron CP-4550 1009281 8314 Xerox 820-II keyboard (Xerox part 110S80564) q7.neurotica.com
? 80-350128 REV. A Cortron SS3 ? ~1983 Prime/Pr1me ESA 5146 keyboard Deskthority
45-500056 ? Cortron CP-4550 1000394 8326 Unidentified, possibly Univac coronthica.com
55-500582 80-551646 REV. C Cortron Series 54 1029395 8406 Unidentified keyboard Deskthority
25-500035 80-250092 REV C Cortron Ferrite core, DIN-compliant, tactile 1019362 8438 Xerox 820-II keyboard Flickr
25-500200 80-250177 REV. H Cortron (Taiwan) Ferrite core, DIN-compliant, tactile 112122 8630 Burroughs B25 K1 AB Deskthority
35-500083 ? Cortron (Mexico?) SS3 1004568 8747 Unidentified keyboard, possibly HP GovPlanet

The serial numbers appear to be monotonic, but on at least two occasions ITW seem to have started a new numbering range. The Taiwan-made example has a serial number from a separate system.

Note that the controller chips on newer keyboards all appear to have part numbers in the range 80-552xxx, regardless of keyboard series. Series 555 keyboards have controller or encoder chips with part numbers in the same 80-551xxx range as the keyboard PCBs.

Two models, 55-500161 and 55-500135, use a Deltrol Controls 100C Series clapper solenoid as a clicker. The underlying device is a conventional solenoid, but Deltrol only have “Core Tron” listed as a customer of this long obsolete part, and it may have been custom ordered with a modification that makes it operate solely as a clicker.


The material below was scanned by Bitsavers unless otherwise noted.