SOLVED What is the purpose of a Dupont 2.5 2X4Pin Power Cable on a mini sas breakout?

[Keven]

hi, i was looking to buy some cheap SFF-8087 mini-sas to 4x sata breakout cable on ebay and found some that have a fifth connector. i found that it is a Dupont 2.5 2X4Pin Power Cable, but i don't know it's purpose.
I'd like to know what is it's purpose?
What it is use for?
If it make a difference vs having a cable without the fifth cable (Dupont 2.5 2X4Pin Power Cable) for an LSI SAS 9210-8i 8-port and some sata HDD?

 

[Samuel Tai]

That's for a controller-specific sideband channel. See https://doc.xdevs.com/doc/Seagate/SFF-8448.PDF. Typically this is for things like the controller sending power on/off signals to the drive before hot-swap, or LED flash to identify a specific drive on a backplane.

 

[Keven]

That's for a controller-specific sideband channel. See https://doc.xdevs.com/doc/Seagate/SFF-8448.PDF. Typically this is for things like the controller sending power on/off signals to the drive before hot-swap, or LED flash to identify a specific drive on a backplane.

OK so, if I understand it won't affect anything if I don't plug this cable with my setup

 

[Samuel Tai]

Correct. If you're not using a backplane with a sideband connector, or your controller doesn't have sideband capability, this cable will be superfluous. The only impact will be on airflow cooling in your case.

 

[Keven]

Thank you for your quick reply