Using more than one USB device on Tablet?

[#1]

I have recently bought one of these.....
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=261462421183
and so far, am quite pleased with it....
however, it seems that I can only use one USB device  at a time on this... and wonder if "rooting" the device will make it recognise more than one USB device when plugged into something like this....
http://www.ebay.co.uk/itm/4-Ports-Octopus-USB-Hub-Cable-New-Portable-Drive-For-Windows-XP-7-Mac-OS-L...
I already have a 4 port USB hub ( that may be faulty - unknown history )... and when I plug the OTG cable into it, it will only recognise one USB  device...e.g. if I plug in my WIFI dongle, and the keyboard,..( although the 2 ports in use have led indication) the tablet will only recognise one... ...
jim:green Second link changed at the request of the OP mod:end

[#2]

Is it a powered hub ?
Often the device can only physically power one device so by using a powered hub, this takes the load off the host.

[#3]

The one I already have is not powered... however, the Tablet was on mains supply when I tried it ...

[#4]

It doesn't matter about the mains for the tablet - the USB port will be specified to output a maximum of either 100ma or 500ma - if you exceed that the device attached will refuse to work in the majority of cases.
If you try it with a powered hub and it still doesn't recognise both devices then your port will only support one device at a time.

[#5]

OK  Thanks for the info....

[#6]

UPDATE.....
The 4 port Octopus USB hub ......
http://www.ebay.co.uk/itm/4-Ports-Octopus-USB-Hub-Cable-New-Portable-Drive-For-Windows-XP-7-Mac-OS-L...
Arrived yesterday, and I have been playing with it on my Android tablet..... the second linky in my original post, should have been the one in this post..  

Up till now, I have been using a mouse, and the keyboard, and accessing the USB memory stick, all on the mains powered supply..... just pulled the plug on the mains and it still works all three... I suspect the battery will suffer, if I should keep using it...but it is nice to be able to use them all together.... got one port left for my 3G  WIFI dongle , when I can find a suitable MBB only suplier, that does "proper" payg...!...

[#7]

Again, if your combined power requirements from the devices (including the hub) exceed that capable of being provided by the port, things will stop working.
Using a powered hub would also stop the drain on the tablets battery although it may defeat the point of a portable tablet lol.

[#8]

first post changed as requested

[#9]

Thanks Jim.