The spread of open systems inter-connections for electronic data exchange throughout a given company in the UK does not follow the classical S-shaped curve so often encountered for the diffusion of new technology. In financial sector organizations the rate of spread of departmental open systems inter-connections appears to be linear, but in the manufacturing/production industry as many inter-connections as are going to be made, less occasionally one, become established within four years of the firm starting to implement its open systems policy. Causes for this four year end point are advanced.