IBM Plant Codes

List of Known Codes
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Content by Tomáš Slavotínek, Tim Clarke, and Christian PL. Last update: 20 Nov 2023


IBM plant codes are 2-digit numbers identifying the facility where a given product was manufactured and/or assembled. These codes can be found on many IBM products - most significantly on assembled units and integrated circuits.

Systems and Other Units

Main units, monitors, terminals, storage units, and various other IBM products typically come with a type/serial number sticker. The unique serial number often starts with a 2-digit prefix - the plant code. Something like this:

S/N 55-2Z0R2

Here the "55" indicates that the machine (IBM PS/2 Model 95) was manufactured/assembled in Greenock, UK.

Integrated Circuits

Similar information can be found on many IBM-made ICs. However, our understanding of the used format and values is very limited at the moment. In general, the code consists of an "IBM" prefix, followed by one or two 2-digit plant codes, terminated by an optional "Q", "P", or "PQ" suffix. Here are a few examples:

IBM 53 52Q
IBM 93 14
IBM 9352PQ
IBM 9352
IBM 98

The spacing between the individual sections seems to be greatly inconsistent and most likely can be ignored.

The "IBM" prefix is self-explanatory. Sometimes it appears in form of the striped IBM logo, but often uses a more pedestrian font shared with the rest of the chip labeling.

It's currently unknown what the "Q"/"PQ" suffix indicates. The most common theory is that it stands for "Qualification" and "Pre-Qualification" respectively. But if that's the case, then IBM shipped an awful amount of pre-qualification IC samples in their products - which seems rather questionable. The rare "P" suffix might stand for "Prototype" (seen on THIS unreleased adapter).

Some chips have a single 2-digit plant number, while others have two 2-digit numbers (4 digits total). The latter variant possibly indicates where the die was fabricated and where the chip was packaged - in cases where the two aren't the same. If this is correct it seems more likely that the first two digits would indicate the assembly line and the other two the silicon fab.

List of Known Codes

Note: Some of the information presented here is currently unconfirmed and may be inaccurate.

00("USA generic"?)
02Poughkeepsie, NY, USA[1]
10Rochester, MN, USAAS/400[1]
11Lexington, KY, USA[1]
14(Burlington, VT, USA?)ICvery common; CMOS?; often as "5314", "9314"
16SwedenVällingby (punchcards) or Järfälla (printers)?[1]
16?ICpossibly recycled code? seen on T3 complex
23Boca Raton FL, USAPC, PS/2, and othersEntry Systems Division (ESD); until 1996[2][3]
26Austin, TX, USA[1]
27("3rd party"?)unitsseen on the "Made for IBM" 7690
31United Kingdom[1]
35France (Bordeaux?)[1]
43Italy (Vimercate?)[1]
44Santa Palomba, ItalyS/36 and othersseen on many 5363[1][2]
51Montpellier, FranceIC[1]
52(East Fishkill, NY, USA?)ICmfg/pkg; very common and long-lived
53(USA?)ICmfg/pkg; possibly also Fishkill?
54Havant, UK
55Greenock, Scotland, UKPS/2 and others[2]
58Amsterdam, Netherlands[1]
65Dublin, Ireland 93b[1]
70?ICalways as "7070"?
72Raleigh NC, USAPC, PS/2, and othersResearch Triangle Park (RTP); 1996 and later[2][3]
77Spain (Valencia?)units
78Guadalajara, Mexico[1]
83Dublin, Ireland 99b[1]
90Wangaratta, Australia[1]
91Don Mills, Canadaseen in a 5291 terminal[1][3]
93Canada (Bromont?)ICmfg/pkg/test?; see HERE and HERE[1]
97JapanPS/55 and others[2]
98JapanICmfg/pkg; mostly PQFP, some metal can PGA[2]
694United Kingdom3-digit code?[1]


[1] IBM typewriter reference (thx Tim Clarke) (see HERE)
[2] Empirical evidence (system units of known origins, etc.)
[3] Confirmed by Joe George (worked for an IBM dealer of midrange systems)


  • Plant codes "53 14" and "93 14" appear on many PowerPC 601(+) CPUs. These chips were produced only at Burlington, VT, USA and East Fishkill, NY, USA. It's however unknown how this maps to the plant codes. The same code combinations can be found on other (CMOS?) chips from the same era.
  • From an ex-IBMer: I worked for IBM for 25 years (from '88-'13). I worked in Burlington, VT in the chip design area. It's likely the IBM chips you see in this would have been made in East Fishkill, NY, which handled the bipolar chips used by the IBM Server group, whereas Burlington handled CMOS chips, more commonly used in IBM's consumer and low-end products like the PC division, at least until the mid 90's when Fishkill eventually switched over to CMOS. [...]
  • In 1996 IBM closed Boca Raton manufacturing (Entry Systems Division) and moved it to Raleigh (Research Triangle Park).

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Content created and/or provided by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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