Cinema Display 20" - seems to work with 2 rather than 3 cables attached

katewes

macrumors 6502
Original poster
Jun 7, 2007
418
90
The Apple 20" matte, silver-frame Cinema Display has three cables: a DVI cable, Firewire and USB.

According to the Apple instructions, all three need to be connected to the MacBook Pro's ports.

I used a DVI-to-MiniDisplay Port to connect the first DVI cable to the MBP's Mini-Display Port.

I connected the USB.

However, I did not connect the Firewire cable (because I didn't have a Firewire converter).

And yet, the Cinema Display seems to work fine with just 2 out of the 3 cables connected.

Why does Apple require all 3 cables to be connected, and am I potentially causing problems to the hardware? Or I am good to go with just 2 cables connected?
 
Last edited:

Gav2k

macrumors G3
Jul 24, 2009
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You only plug the usb and FireWire in if you want to use the port replicator on the back of the display.
 

katewes

macrumors 6502
Original poster
Jun 7, 2007
418
90
You only plug the usb and FireWire in if you want to use the port replicator on the back of the display.
Thanks. So if I want the port-replicator, do I need to connect both the USB and Firewire, or will just one of those suffice?
 

Gav2k

macrumors G3
Jul 24, 2009
9,218
1,584
USB will enable the USB ports and FireWire will enable the FireWire ports
 

katewes

macrumors 6502
Original poster
Jun 7, 2007
418
90
USB will enable the USB ports and FireWire will enable the FireWire ports
Thanks. That makes so much logical sense. It's a pity that the Apple instruction manual did not explain that so clearly. The manual just said plug it in, without explaining what would be the result of plugging in the various cables.
 

Gav2k

macrumors G3
Jul 24, 2009
9,218
1,584
That's what forums are for. To ask simple questions and get a simple answer back.
 

katewes

macrumors 6502
Original poster
Jun 7, 2007
418
90
That's what forums are for. To ask simple questions and get a simple answer back.
Gav2K, you wouldn't happen to know if two such Cinema Displays -- with DVI cable -- can be attached to a mid-2012 MacBook Pro?