The African Reference Alphabet was a proposal for characters to be used in writing the languages of Africa, developed at meetings in Niamey, Niger in 1978. Two of the participants in that work, David Dalby and Michael Mann, went on to revise that proposal, and further proposed a standardised keyboard layout, which they called the “international niamey keyboard”.
Note that one of the differences between the original 1978 proposal (see charts of the African Reference Alphabet) and Mann and Dalby's revision is that the latter does not use case. Mann and Dalby comment, “it is our view that no language requires upper and lower case varieties of every letter for its transcription, and we consider that the textual use of capital letters could be abandonded [sic] without detriment… to insist on the use of capitals in the writing of african languages is to impose on these languages an unnecessary western european convention...”1 Clearly, abandonment of capitals has a very significant impact on the design of a keyboard layout since there are only half as many characters to support.
1 Their book would be easier to read had they not also abandoned capitals for English.