NCR S26 - Manual (Page 32)

Configuring the System Board
2-14 Using System Features
Connector Function
CN11 68-pin Wide SCSI connector
CN12 50-pin Fast SCSI-2 connector
CN13 Power LED connector and RDM switch cable from front of unit
CN14 Hard disk LED connector
CN15 No connection
CN16 Speaker connector
SW1 NMI switch