Epson Grayscale Scanner - Manual (Page 7)

7. If you are connecting the scanner directly to your Macintosh,
connect the 25-pin connector on the dual-connector end of
the cable to the SCSI port on the Macintosh; this port has
a
icon above it. Tighten the two screws on the sides of
the connector.
If you are connecting the scanner to another SCSI device in a
daisy-chain, connect the 50-pin connector on the cable to
the SCSI device.
5 Getting Started