Intel Q77 Technical Manual page 19

(3) ATX12V (4-pin block): ATX12V Type Power Connector
(4) SATA1/SATA2: Serial-ATAIII Port connector
These connectors are high-speed SATAIII ports that support 6 GB/s transfer rate.
Pin1
Pin No. Definition
1 GND
2 GND
3 +12V
4 +12V
Pin No. Defnition
1 GND
2 TXP
3 TXN
4 GND
5 RXN
6 RXP
7 GND
14