|-
|#FBEC||?||[[KDS_Electronics_Serial_Interface|KDS RS232]] 6850 (reversed bit-order) Control||-||Write
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|#FBEC||?||[[PDS development system]] Data||?||?
|-
|#FBED||?||[[KDS_Electronics_Serial_Interface|KDS RS232]] 6850 (reversed bit-order) TX Data||-||Write
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|#FBED||?||[[PDS development system]] Handshake||Read||Write
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|#FBEE||?||[[Amstrad SSA-1 Speech Synthesizer]]||Read||Write