HP D2000 Disk Enclosures - Manual (Page 14)

I/O module
The I/O module provides the interface between the disk enclosure and the host.
Each I/O module has two ports that can transmit and receive data for bidirectional operation.
Large Form Factor I/O module Small Form Factor I/O module
4. Double 7–segment display 1. Manufacturing diagnostic port
5. I/O module LEDs 2. SAS Port 1
3. SAS Port 2
I/O module LEDs
LEDs on the I/O module provide status information about each I/O port and the entire module.
NOTE:
The following image illustrates LEDs on the Small Form Factor I/O module.
Hardware 14