Figure - Maxtor DiamondMax 17 80 ATA Installation And Use Manual

Installation
3.4.2 External Drive Activity LED
An external drive activity LED may be connected to the DASP-I/O pin 39 on J1.
For more details, see the pin description in Table 5-1.
3.4.3 ATA Bus Interface Connector (J1, Section C)
On the DiamondMax 17 80-160GB AT hard disk drives, the ATA bus interface
cable connector (J1, section C) is a 40-pin Universal Header, as shown in Figure 3-5.
To prevent the possibility of incorrect installation, the connector has been keyed by
removing Pin 20. This ensures that a connector cannot be installed upside down.
See Chapter 5, "ATA Bus Interface and ATA Commands," for more detailed
information about the required signals. Refer to Table 5-1 for the pin assignments
of the ATA bus connector (J1, section C).
3-10 Maxtor DiamondMax 17 80-160GB AT Hard Disk Drive