Serial number collage

Serial Numbers

BBC Micro serial numbers fall into two broad categories: numeric and structured. Numeric serial numbers were used until roughly August 1983, when they were replaced by structured serial numbers.

Numeric Serial Numbers

Numeric serial numbers were used by ICL, Cleartone, AB and Race. These serial numbers are six digits long, with blocks of 100,000 being assigned to different manufacturers, as follows:

  • 000000 - 099999: ICL
  • 100000 - 299999: Cleartone and AB
  • 300000 - 399999: Race

Cleartone was taken over by AB and it seems that the serial number sequence continued under the new ownership. The highest known Cleartone serial number is 110778 and the lowest known serial number used by AB is 112359. Some AB machines with serial numbers higher than 200000 have a new structured serial number on the case, whilst the numeric serial number is assigned to the PCB.

Some example serial numbers:

  • 012345: ICL
  • 101234: Cleartone
  • 112359: AB
  • 201234: AB (with an accompanying serial number in the ANB range)
  • 312345: Race

The full range of each allocation was not used. The highest known serial numbers in each sequence are:

  • ICL: 029779
  • AB: 205756 (with an accompanying serial number in the ANB range)
  • Race: 324313

When structured serial numbers were introduced, manufacturers were assigned two digit codes. In the case of AB and Race, these codes were based on their numeric serial number range allocations. AB became ‘01’ and Race ‘03’.

Unlike structured serial numbers, the type of machine (Model A or Model B) is not encoded within the number, so it it not possible to definitively know a machine’s configuration from that alone. However, it is possible to generalise:

  • Most ICL machines are Model B
  • All Cleartone machines are Model A, except for a few Issue 1 Model Bs.
  • Most AB machines with a serial number above approximately 115000 are Model B, lower numbers are likely to be Model A.
  • Most Race machines are Model B.

Examples of Numeric Serial Numbers


The serial number labels on the cases of approximately the first 1,000 machines produced by ICL had the company’s logo removed. This appears to have been done by cutting the label after it had been applied to the case:

ICL serial number with logo removed

The PCB also had a serial number label which sometimes retained the ICL logo. The remaining 29,000 machines built by ICL had a complete label on the case:

ICL serial number with logo


Cleartone’s serial numbers are dot matrix printed on plain white labels. The labels appear to be hand-cut from a larger sheet.

Cleartone serial number


Numeric serial number labels used by AB are identical in style to Cleartone’s, due to the fact that AB took over Cleartone’s manufacturing facility. The earliest labels show the company’s name as AB ELECTRONIC SYSTEMS PCL.:

AB Electronic Systems PCL. serial number

The error is corrected between serial numbers 114420 and 114437:

AB Electronic Systems PLC. serial number

Between serial numbers 148263 and 151920, PLC is changed to Ltd:

AB Electronic Systems Ltd. serial number


Race serial number labels are pre-printed with Race’s logo in blue, with the number stamped on in a closely-matching colour. It is a shame that the logo did not continue to be used on the company’s structured serial number labels.

Race numeric serial number

Structured Serial Numbers

Structured serial numbers encode more information than their numeric counterparts. They contain the product type, variation and manufacturer and have the advantage (to Acorn, at least) of concealing the name of the subcontracted firm which built the computer.

Various formats were used, possibly because the standard was only loosely enforced by Acorn, or possibly because the manufacturers’ serial numbering equipment limited what what they were able to put on the label. However, Acorn’s structured serial numbers are usually in the following format:


The parts are as follows:

  • MM: Manufacturer code - two digits
  • PPPPP: Product code - three letters followed by two digits
  • NNNNNNN: Serial number - seven digits

An example serial number is:


There is more structure within the product code and serial number. The product code has the format:


  • TTT: Product type - three letters
  • VV: Product variant - two digits

In the example above — ANB01 — the product type is ANB (a BBC Model B) and the product variant is 01 (no disc or Econet interfaces fitted).

The first two digits of the serial number are determined by a combination of the manufacturer code and product code. In the case of 01-ANB01- serial numbers, the first digits of the serial number are always 30. The first two digits for 01-ANB02-, 01-ANB03- and 01-ANB04- serial numbers are 40, 50 and 60 respectively.

As with any well-defined system, there are exceptions. Various manufacturers used serial numbers which do not fit into the MM-PPPPP-NNNNNNN. All known types of structured serial number are listed below.

Examples of Structured Serial Numbers

AB Electronics

AB’s structured serial number labels are white with a black border. The adhesive is not particularly strong so many of these type have fallen off over the years. The digits zero and one in the manufacturer and product codes are actually a capital letter ‘O’ and ‘I’, though the reason why this was done is unknown.

AB structured serial number

It seems that AB were also allocated the ‘07’ manufacturer code. Perhaps this applied to a different factory owned by the company.

07 structured serial number


Manufacturer code 02 belonged to Wong’s Electronics in Hong Kong.

The first structured serial numbers issued by Wong’s Electronics use a shorter product code and only six digits in the serial number section, instead of the more usual 7. These seem only to have been used on UK-specification Model B machines

Wong short structured serial number

The format is MM-PPP-NNNNNN, giving serial numbers that look like this: 02-B01-212345. Only the final letter of the product code is used, with ANB being shortened to B. The first digit of the serial number is still fixed, and in this case it is a 2.

Wong later adopted the standard format for their structured serial numbers, and this can be found on later UK-specification machines as well as the export specification Model B machine for the US and German markets. Wong were the only manufacturer or US and German specification machines.

Wong structured serial number


Race serial numbers omit the dash between the manufacturer code and product code and put the serial number on a second line.

Race structured serial number

These serial numbers are usually written in the format MMPPPPP NNNNNN, with no dashes and a space before the serial number component. A typical serial number looks like this: 03ANB01 3012345.

Manufacturer 06 (Unknown)

Manufacturer 06 uses a similar format to Wong - MMPPP NNNNNN - but omits the first dash and replaces the second with a space, being written as follows: 06B01 112345.

06 structured serial number

Like Wong, the serial number component is six digits instead of seven. The initial digit is always 1. There are very few examples of this type of serial number and they have only been seen on Model B machines.


Keltek are the only manufacturer whose name appears on a structured serial number label. The majority of the company’s output was Issue 4 Model Bs, all with serial numbers in the 08-ANB01 range. The serial number labels for these machines look like this:

Keltek serial number

Keltek also produced some computers with ANB03 and ANB04 product codes (Model B with disc interface and Model B with disc and Econet interfaces respectively). The serial number labels for these are dot matrix printed:

Keltek serial number

Manufacturer 09 (Unknown)

Manufacturer 09 uses labels with look similar to Keltek’s. Unfortunately there is no manufacturer name so it is not possible to know which company produced these computers.

09 serial number


The ANB100 serial numbers do not conform to any of the formats described above. They are all applied to Model B machines with an Issue 7 board.

ANB serial number

The format is ANB100 NNNNNN, meaning that there is no specific component which identifies manufacturer. It consists simply of a shortened ANB01 product code with two additional zeros, followed by a 6-digit serial number. The first digit is always 1 and it is possible that the second digit is always 0, giving space for a range of only 0 to 9999 for the serial number itself.