Lenovo THINKSERVER 3821 - Manual (Page 172)

The following illustration shows the internal SAS/SATA cable routing and connectors
from the ServeRAID BR10i controller to eight 2.5-inch hard disk drives. The left port
on the ServeRAID BR10i controller is connected to the backplane for drives 4-7 and
the right port on the adapter is connected to the backplane for drives 0-3.
1 Cable for drives 4-7
2 Cable connector for drives 4-7
3 Cable for drives 0-3
4 Cable connector for drives 0-3
164 ThinkServer TD200x Types 3719, 3821, 3822, and 3823: Hardware Maintenance Manual