SCSI bus timing

Disconnection delay

Negation period

SCSI-2

5.7.11 Hold time

The minimum time added between the assertion of REQ (or REQB) or ACK (or ACKB) and the changing of the data lines to provide hold time in the initiator or target while using synchronous data transfers. REQB and ACKB timings only apply to optional wide data transfers.