Backplane inter-connect cable purpose?

[Dispatcher]

I recently purchased an HP ProLiant DL160 DL165 Backplane kit. It includes installation instructions, the backplane, screws, a little cable that apparently can connect the two backplanes together. However the installation instructions don't say to use the cable, or what the cable is even for.

These are SAS drives on a 1U server. Anyone know what this little jumper cable is used for? I don't want to plug it in if it's not necessary, but I don't want to exclude it if it is necessary for some feature I'm not aware of.

[Zygmunt Krawczyk]

HDD backplane has mini-SAS connector, power connector, and 3-pin I2C connector. Probably this little cable is I2C cable. You need connect this cable to the I2C connector on the system board.

[Dispatcher]

What's it for though? The backplane works without it.

[Zygmunt Krawczyk]

>> The backplane works without it

OK, bacplane works, but is not monitored. I2C is used for diagnostics and monitoring sensors in backplane.

[Dispatcher]

Ah! Ok, thank you, that's what I was wondering. Great. I'll attach it.