How to connect two non-Thunderbolt displays to the Macbook Pro 2011 via Thunderbolt?

Question

I have the VGA and HDMI adapters for my Macbook Pro 2011, but can only connect one display at a time - neither adapter has a female Thunderbolt connector to act as a passthrough.

My understanding is that I can use two Apple Thunderbolt displays by daisy chaining them and have three displays - the native notebook display, and two Thunderbolt displays - at once.

• Is there a way to connect two non-Thunderbolt displays to the laptop, via a splitter, or some sort of Thunderbolt cable or adapter?

• If I buy one Thunderbolt display, can I then use the VGA or HDMI Thunderbolt adapter daisy-chained off that display to drive a non-Thunderbolt display and have three monitors that way?

Answer 1

The Apple mini-DisplayPort to VGA or HDMI adapter terminates the Thunderbolt chain where it is connected, so until Apple released new MacBook Pro with two Thunderbolt ports (similar to the iMac that has two ports) then you will only get one video signal from the device through the Thunderbolt port.

You may find an inexpensive USB to VGA solution to get around this limitation. Initially they were slower, but the newer ones are getting much faster and the software much better. You can then put the most important content on the Thunderbolt port and have the secondary display served over USB.

Should a Thunderbolt adapter come about that drives two displays, I'll update the answer, but nothing has been released (or even rumored) even though it's clearly something the protocol could support.

I like this knowledge base article for the clear deprecation of which Macs support two Thunderbolt displays and which ones only support one.

• Apple Thunderbolt Display (27-inch): Connection options for Thunderbolt Macs

Answer 2

This MacRumors article notes:

Apple's notes one other caveat about the Thunderbolt display: older Mini DisplayPort displays won't light up if they're hooked directly into the Thunderbolt port on the newer LCD. Macworld's testing found that Mini DisplayPort LCDs can be added to a Thunderbolt chain and work as normal by hooking them into another Thunderbolt peripheral. It's unclear why simply hooking the older monitors directly into the newer ones doesn't work. For best performance Apple recommends hooking the Thunderbolt display directly into the Mac's port, then hooking Thunderbolt storage devices into the display's relevant port.

From Apple Support's KB:

Mini DisplayPort displays will not light up if connected to the Thunderbolt port of an Apple Thunderbolt Display (27-inch). Displays connected via Mini DisplayPort video adapter to the Thunderbolt port of an Apple Thunderbolt Display (27-inch) will not work. Connect Mini DisplayPort displays directly to a Thunderbolt port on a Thunderbolt-capable Mac or to a compatible Thunderbolt peripheral. If the Mini DisplayPort display is connected to a Thunderbolt peripheral, the display should be connected at the end of the Thunderbolt chain.

From another Apple Support KB:

Connect Mini DisplayPort displays directly to a Thunderbolt port on a Mac or to a compatible Thunderbolt peripheral; do not connect a Mini DisplayPort display to a Thunderbolt display. Use only one Mini DisplayPort device in a Thunderbolt chain. You cannot use a Mini DisplayPort to Mini DisplayPort cable to connect an iMac (Mid 2011) in Target Display Mode to a Thunderbolt chain. See iMac (Mid 2011): Target Display Mode does not work with Mini DisplayPort cable for more information.

I don't have the right hardware to test this setup, but the article/KBs above imply that driving multiple monitors may be possible, depending on your MBP model (see this KB for more details) regarding the number of monitors that are supported. Some MBPs with integrated graphics can only support one Thunderbolt monitor, which may preclude three monitors from being used together.

Answer 3

This question from July 2011 came to the conclusion that there wasn't a display splitter available yet and it seems there still isn't as far as I can search.

My feeling is that it's going to be an expensive device when or if it appears - probably more along the lines of a Thunderbolt-connected video upgrade (because Thunderbolt allows PCIe bus extension it may be a chassis allowing use of an off-the-shelf video card with dual outputs) rather than a simple adapter like the current DVI or HDMI adapters. Expect more products like this to appear.

This is one potential way to get two displays - if the software issues are solved, the product page says it does not currently work pending support from Apple - but I don't know what it might cost!

Answer 4

There are cheap DisplayPort to HDMI splitters, all based on the IDT ViewXpand chipset. You do not get full control over your monitors, mind you, to the OS it's just one huge monitor. But, did I mention it's cheap? http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10114&cs_id=1011409&p_id=8117&seq=1&format=2 or http://www.newegg.com/Product/Product.aspx?Item=N82E16812500002 . I plan to drive a T221 from the two DisplayPorts on the 2012 MacBook Pro. 14 megapixels from a 2kg one laptop, that'd be something :D

Edit: to clarify, this is a hack. This is not a MultiStreamHub for DisplayPort.

Answer 5

I searched hard to find something that will enable me to use 2 displays from my 2012 MacBook Pro without sacrificing on a USB port (by using an external graphics card)

My search ended here.

Basically this beauty enables me to plugin into the thunderbolt port (which also take Mini display ports) and connect 2 x 24 inch monitors using HDMI AND also use my MacBook Pro display.

So in total I have 3 displays all running at the same time.

What this adapter does is create an external display spanned across 2 monitors, which I have no problem with as i can resize my application windows accordingly. And plus you get lovely HDMI resolution. Hope that helps.

Answer 6

Go for the PSE-DP4196.

Looks like a winner!

Answer 7

You can by interface miniDP -> DVI and switcher

You can find cheaper but they won't support 2560x1600px resolution on each monitor.