One Hundred (100) IBM model M keyboards for sale: * SOLD * November 11, 2004 *

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IBM model M keyboards are one of those components of legend among computer professionals who "know" quality. UNIX / Linux programmers, 3733t hackers, custom case mod ’puter builders, professional transcriptionists, certified MCSE pros, and old school computer system operators regard them with special admiration.  It is one of those late 20th century electronics that will still be useful, well into the 21st century. 

In almost every computer message board thread about "the best keyboard" on www.slashdot.org or any number of other specialist web sites (www.arstechnica.com, www.anandtech.com, www.dansdata.com www.somethingawful.com) expert users will always recommend the "IBM model M keyboard" to the un-informed newbies who mistakenly "think" that a good keyboard is one that has extraneous buttons, soft-touch ergonomic keys, or is rubber-made and can roll up into your pocket, or has shiny parts and flashy glow-in-the dark things.  These keyboards have a particular underground popularity among the Japanese elite collectors/buyers.

When used in an office or other LAN environment, everyone in the room knows by the distinctive "machine-gun like" mechanical typing sound that you have a real keyboard.  Weighing 5 pounds (2.2kg), they are that "made in the USA" tool that every computer craftsman must have in their arsenal. 

With their strength and durability, it is the rare computer component that you can pass down as an heirloom to your kids or to the next generation.  This keyboard clearly distinguishes elite professionals from simple computer users.

update: November 11, 2004: Lot of 100 keyboards has been sold to three vintage hardware collectors from Atlanta, Georgia.


Analysis of 125 IBM model M keyboards

One of the distinguishing marks of these IBM model M keyboards is that in addition to their mechanical "clicky" buckling-spring key-switches and known durability, each keyboard is individually labeled with a production label on the rear face of the keyboard, or a "date of birth" certificate. Among the information that it details are the specific IBM part number, individual serial number, date it was produced.

By looking at the "birth certificate" info, we thought that by carefully recording and tabulating all the info that we would be able to extrapolate an estimate of how many of these keyboards were produced over the lifetime of the model. At one time we used to teach statistics and analytical methods at the university level. We were hoping that we could apply statistical analysis methods to the project. We originally considered doing this several years ago, but were not satisfied with a sample size of 10, 20 or 30 keyboards. We also considered using the data of others posted online, but we were unable to always verify that the information was complete and accurate. It was not until recently that we were able to physically collect a specific population of 125 of these keyboards at one time.

Keyboards were obtained from a variety of sources throughout the United States, purchases at local computer surplus outlets, purchases from private dealers, or trades with other collectors, a subset were purchased on the online auction site, eBay. Six keyboards were purchased from outside the United States, London, England (part # 1391403), Germany (part# 1391406), Mexico (#1391401)

1. UNIQUE IDENTIFIER: Each IBM model M keyboard has a unique serial number. In no cases, did we find that there were duplicate serial numbers either within an IBM part number (1391401) or across IBM part numbers series (1391401 vs 42H1292)
2. NO SEQUENTIAL SERIAL NUMBERS: Among the 125 keyboards we looked at we never saw two keyboards with serial numbers appearing in a sequential sequence. This was unexpected, even though we found IBM keyboards that were born on the same calendar date. We expected that we may find the keyboards born on the same date that might have sequential numbers, indicating they they came off the same batch. This suggests that there may be a fixed interval that is greater than one between serial numbers.   (update: August 2005, we recently have found a batch of 1390131 keyboards made in 1996 that were had consecutive numbers from 000249 - 000267.. another batch was numbered from 0000093 - 0000099.  So we conclude that at least some of these keyboards have mod +1 serial numbers.) 
3. EARLIEST SERIAL NUMBER/DATE: The earliest IBM model M keyboards that we currently hold in the collection was from December 12, 1985 (part# 1388032, serial # 05548). We have seen other online evidence of an other early model M keyboard owned by a collector in Japan (January 13, 1986, part# 1390120, serial # 10732). 
   
   Note, we have seen several online references of people referring to their keyboard as originally produced in 1984.  This error probably originates from the fact that the label on IBM model M keyboard also has the following text imprinted on it: © IBM Corp 1984.  This information reflects the year that the original design was copyrighted.  It does not reflect the date of production.  The original specific date of production always includes information about the specific date and month, in addition to the year.  We have NEVER seen an IBM model M keyboard with an original date from 1984.
4. DIFFERENCES IN SERIAL NUMBERS: The smallest serial number were numbers 603, 1943, 3498. The largest serial numbers were 8984323, 8918379, 8824170. Initially we thought that with a large enough sample size that we would be able to estimate the total number of keyboards produced by subtracting the largest from smallest serial number (8,824,170 - 603) = approximately 8,823,567. We do not believe that 8 million of these keyboards could have been produced in the years between 1985 and 1999.
5. DETACHABLE KEYBOARD CABLE: IBM keyboards with part numbers 1390120 and 1390131 were originally bundled with detachable keyboard cables that were black in color and terminated in the 5-pin AT connector. 1391401 keyboard were originally bundled with detachable keyboards cables that are gray in color and terminated in the smaller 6-pin ps/2 connector. Many of the keyboards with part numbers 42H1292 have an attached cable with ps/2 connector
6. FACTORY PRODUCTION: We suspect that model M keyboards were made in various factory locations. We know from other information, that early IBM keyboards were made solely by IBM in Lexington, Kentucky. In later years, keyboard production was also done by Lexmark, Unicomp and IBM - United Kingdom. We also learned that another keyboard producer, (Maxi-Switch), also produced IBM model M keyboards (specifically the IBM model M-13 trackpoint keyboard (13H6705 or 13H6710) in black). On the back label of most (but not all of the keyboards) is the following txt: Plt No. Values range from 78 (Mexico), F1, F2, F4, F7, J1, J2, I1, IED (United Kingdom), L1, LI-MH, TC1. We are unsure if this abbreviation is for "plate number" as in master template used for construction or perhaps "plant number" as in physical location of construction plant.
7. IBM LOGO: There are four types of IBM logos that were found on these keyboards, the oldest is the IBM logo printed in silver text on black aluminum square place (1985), black text on an aluminum square plate (1986 - 1987). Then the IBM logo printed in black text on a white oval (1987 - 1992). Next there was the IBM logo printed in blue text on a gray oval (1992 - 1995). The last type is similar to the previous one, except the IBM logo printed in blue text is on a slightly darker gray oval (1996 - 1999).
8. OTHER LOGOS: In addition to IBM logos, these keyboards were also produced with labels of other manufacturers (Lexmark, and Dell original logo and Dell newer "standard" logo).
9. TRACKBALL and TRACKPOINT VARIANTS: In addition to the standard 101-key enhanced keyboards, IBM also produced these keyboards with additional features. IBM model M13 (82G3281 (white) and 13H6705 (black)) have a built-in pointing stick between G and H keys. This is similar to that commonly found on laptops and originally introduced on IBM Thinkpads. IBM model M5-1 (1370478) and model M5-2 (92G7456) come with built-in trackballs that can be used as pointing device. Both the M13 and M5 lines come with specialized keyboard cables that have two independent terminal connectors. One connector plugs into the standard keyboard port and the other plugs into either the mouse port or 9-pin serial port.
10. KEY CAPS AND LETTERING: On the majority of these keyboards, the keys which form the actual lettering of the keyboard are either detachable from key stem. On a smaller minority, these come in one-piece key cap-stem assembly. For the 2-piece detachable key cap - key stem models, the key caps are physically interchangeable across the model M series (i.e., key cap from 1985 model could physically fit on 1999 model). However, across different years and locations of production, there are notable minor differences in lettering used. Minor differences include the size of lettering, color of lettering, position of lettering. Another distinguishing feature of the Model M keyboards is that the lettering is embedded into the plastic.  In contrast, many modern keyboards use stickers or silk-screened paint to label individual keys.  Over time, modern keyboards may wear out.. while we have never seen a Model M keyboard loose its lettering.
11. CUSTOM KEY CAP LETTERING: On three of the IBM model M keyboards, there appeared custom key caps. It is unclear whether or not these were originally produced by IBM or were custom-modified after delivery by a secondary retailer. One of the keyboards was identified for use by the airline industry, another for use by banking/investment market industry, and one appears to be designed for a terminal operator or systems programmer.
12. BUCKLING SPRING DIFFERENCES: Differences in "clickyness" There are some marked differences in the sound and feel of the buckling spring that we observed across all 125 keyboards. Some keyboards felt and sounded louder and felt more responsive, than others. Upon cursory, physical inspection all the buckling springs appear similar. However, without the proper measurement equipment or extensive disassembly and examination, we are unable to determine if there are actual differences in the buckling-spring mechanisms used, or if the "clickyness" condition differences are due to age or the amount of use each keyboard received.