A SCSI bus extender apparatus coupling a main SCSI bus to a auxiliary SCSI
bus includes a mechanism for detecting and processing SELECTION and
RESELECTION signals transmitted between the two buses to accommodate
target devices on the auxiliary bus which support tagged queuing in accordance
with the SCSI protocol. The invention contemplates reserving an address on
the auxiliary bus for each initiator on the main bus and performing the
appropriate address conversions to enable target devices to properly identify
the correct initiator device during a RESELECTION phase.