DLink 2540U distribution of an Internet on 3 computer, is it possible to limit the bandwidth on 1 computer?

it seems to have QoS, you can define sorts-ip, and bandwidth. Read the user manual.

I have a unit in any of the firmware nothing like the shaper did not notice.

And rinse the brain of a tech support vendor for forum.d-link.ru have not tried?

I think the easiest way to limit the speed on your computer (find approp. software) and to make the invisible and startup
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"...The D-Link DSL-2540U does not have the traffic shaper this function are expensive devices SOHO, for example D-Link DSL-G804V DSL-2740U.
But they cost between 150-220 dead raccoons, but umeeyut respectively at the proper level already.There is already a VPN support and a lot of useful things plus Wi-Fi.©
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It need a modem with a function of the shaper.
2540 do not know how. As an option — you can configure the entire Internet through your computer, on the computer, to lift NAT and shaper ..."