Recollections of BBC engineering from 1922 to 1997
The British Broadcasting Corporation
web site is:

Designs Department Manufacturing Information, Technical Memoranda and Handbooks

Home Up

Manufacturing Information (DDMI) documents were produced for use by Equipment Department and commercial companies that made designs under contract and/or licence.  At present there are no samples on BBCeng, but much of the information is included in other documents.

Technical Memoranda (DDTM) were written and issued by Designs Department to fulfil one of the following major needs:

  1. To describe the functioning and maintenance of a piece of equipment designed in the department, and thus act as a provisional handbook for the equipment.
  2. To give a factual report on commercial components or apparatus which may be of interest to the BBC generally, or describe modifications to commercial equipment.
  3. To describe the performance of communication circuits.
  4. To describe-system tests carried out with independent observers.

Usually the best way to find the number of a DDTM on a specific topic is to do a search in this list of DDTMs

Designs Department Handbooks (DDHB) were produced for most of the more significant items of equipment that were designed in the Department. They describe the equipment in detail and provide guidance for installation, operation and maintenance.  For some years handbooks were issued as DDTMs, but more recent handbooks were issued as DDHBs.

The serial numbers for the above documents were allocated for each Section of Designs Department e.g., so 6.123 and 7.123 are different documents.

Only one set of serial numbers was allocated within a Section and they were prefaced by the type of document (DDMI, DDTM, DDHB). So, DDTM 6.123 could not exist if the number had already been taken by DDMI 6.123.  (Although this does seem to have happened a few times!)

In all cases the serial number is followed by the year of publication in brackets.

For example DDHB 7.187 (72) was a Handbook produced by Section 7 (Recording Section) in 1972.

Please refer to a Technical Documentation Cross Reference book on this page to find the DDTM/DDHB number for a piece of coded equipment.  e.g. to find the AM15/503P handbook, look for this code in the left column of the "Technical Documentation Cross Reference 1988", then find 1.103 in the DD Handbook column.

Some handbooks that have been scanned by Nick Cutmore can be accessed by the links below.

A series of Technical Instructions called Apparatus in Code Order contain information that is similar to that found in DDHBs, but they were produced by BBC Technical Publications unit and intended for a wider readership in the Operation and Maintenance departments.  This is the largest collection of information on coded equipment that is published on BBCeng and some DDTM/DDHB documents are included.

More handbooks are in the Vault.



New in Aug 2020:

2.464 (82) Zelda Development System Handbook - Introduction & Hardware (Part 1)

2.465 (82) Zelda Development System Handbook - Firmware (Part 2)

2.466 (82) Zelda Development System Handbook - Utilities (Part 3)

2.467 (82) Zelda Development System Handbook - System Software Interfaces (Part 4)




3.186(76) Peak Programme Meter Tester TE1/25 New in June 2020













5.112(76) Stereo VHF Modulator MD1/4 New in June 2020



More handbooks are in the Vault.