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The Roland OP-8 interface was designed to control Roland polyphonic synthesizers that were equipped with a DCB (Digital Control Bus) interface via the Roland MC-4 Microcomposer.[1] The OP-8 and synthesizer were connected together using a DCB cable. The OP-8 and MC-4 Microcomposer were then patched together using patchcords via each of their patchbays.[1] The transpose control on the OP-8 was able to transpose the synthesizer up or down by one octave.[1]
The Jupiter 8 needed minor changes in its circuit for setting up with the OP-8. This work was carried out by Roland.[1]
When using the OP-8 with a Roland Juno 60 the connection and operation were extremely easy, as only the CV and gate input jacks, and the transpose switch were relevant.[1]