15 USB station limit on MPS 2011???


I have DC 125s and Multipoint Server 2011 premium. I connect 14 stations just fine, but when I add station 15, the monitor will not display. The blue light comes on the DC125 and the caps lock illuminates on the keyboard and the laser mouse lights up. What am i missing?


Hi Trey,

Thanks for posting! Yes, Windows Multipoint Server 2011 supports up to 14 USB terminals like the Plugable DC-125 (http://plugable.com/products/dc-125) per server. The limit is influenced by performance and also USB 2.0’s hard limit of 127 devices and hubs per host controller (with 14 stations, you’re already up to around 90-100 depending on your USB topology).

DisplayLink gives a little more background on the technology and the limits at http://displaylink.com/zero_client/in…

How many terminals were you hoping to get up to? And are you finding the performance at 14 stations/server good enough, or were you already looking at partitioning for performance reasons?

And we’d love to hear more about your setup - not enough people realize the interesting possibilities with Windows Multipoint Server and USB clients like our DC-125.

Thanks again!


thanks for the quick reply. Yes, after posting this, I finally found the doc where the 14 USB limit is mentioned. We had 2 extra students added and it bumped 2 of my classes to 15 students so i need that 1 additional station. I hate to have to add a RDC unit as the 15th station. Any recommendations on what else I may be able to add that is similar to the DC125? What I have so far has been working great with 14 stations connected!!! Thanks again! I gotta find a solution for that 15th unit.


Hi Trey,

Unfortunately, to get that one additional unit, we can’t do it on the USB 2.0 bus.

One possible solution: Windows Multipoint Server has the ability to use the server’s in-built graphic card(s), along with an extra keyboards misc connected to the USB ports on the main machine, as extra terminals.

If the server has a VGA port and 2 spare USB ports, have you already tried connecting the 15th terminal that way?

Unfortunately, if we can’t get that going, we may need to go to an RDP (ethernet) terminal for that 15th!

Let us know - we’ll help in every way we can. It’s great to (almost!) see a whole classroom’s worth of students sharing a single machine.

Best wishes,


Thanks!! You know, I tried that early on in the process and seemed to have some difficulty getting the keyboard to trigger, so i hadn’t tried since. Today I revisited connecting #15 to the server but left the mouse and the keyboard on the DC125. Success!!! 15 are up and running! Any idea if there will ever be support for more than 14? This solution is great for this year but if we add any additional students above 15, I will need a different solution. :slight_smile:


Wonderful! Glad we could get you up to 15.

Unfortunately, there’s no way to get above 14 on a single server with USB alone right now – you’d need to add more internal graphics cards (+USB keyboard/mouse) or Ethernet (RDP) clients in the mix, to supplement the 14 USB terminals.

Generally what we’d recommend if you have a 15-28 person class is having two servers in the room, rather than one, and split the USB terminals between them – both because of the 14 terminal limit, and for better performance.

Of course, you can also use it as a reason to insist on smaller class sizes (ha!)

Hope that background helps. Glad to have you up and running with 15 on one server!

Best wishes,


Hi Trey,

How did you connect the 15th one? Did you connect the monitor for the #15 client to the server and left the mouse and keyboard connected on the client? Or did you connect the client to the server direct?