Why do USB hub's have only 4 ports

[kbrady]

I have five USB 2.0 hub successfully operating over 20 devices. As these fail I will upgrade to 3.0. Anticipating more 3.0 devices and a 3.0 motherboard in the future. Why do they only have four ports? If I am mixing 2.0 hub with 3.0 hub's should I plug in. In a certain order

 

[zigzag3143]

I believe partially because of design (where would you put any more) on laptops, and because USB runs on +5v. More than 3-4 unpowered devices decrease the voltage. If you have many un-powered devices the mfr's either have to build a more robust system (which we would pay for) or limit the number of ports.

Those who have more have to buy a powered USB hub which fixes both issues, those who dont have many would not have to pay $$ for it.

 

[seavixen32]

You are restricted to 4 ports because of power considerations, as explained in this article.

USB hub - Wikipedia, the free encyclopedia

Otherwise, buy a powered hub.