PC usually have more than 4 USB ports, especially desktops. Why should there be a limit for the number of k8055 card supported? Very curious…for people working on robotics, wouldn’t it be cool if the PC can have 100++ digital output, think of the amount of servo motors it can control.
If it was servo’s I wanted to control, I think i would use a controller that was made just for that 
I have done some experimenting with servo’s used for RC cars, can see more about it here youtube.com/watch?v=kuoijfs4KBk (only a test setup to show them moving, not really doing anything), could control 16 with one usb port.
Each individual K8055 card has to have individual “address”.
The address “space” of the cards is limited by the address coding hardware on the K8055 board. There are only two jumpers SK5 and SK6 for that purpose. Only four addresses are possible to code.
In the K8061 (Extended USB Interface Board) there are four jumpers for the address coding. This allows eight cards to be connected to the PC. So the total number of analog inputs will be 64, analog outputs 64, digital inputs 64 and digital outputs 64.
oh i see, the number of cards is limited by the card address, 2 bits = 4 combination…
Thanks for the info.
I have a new problem, the k8055 wasn’t being detected by the computer i’m using for my project. please check out the new question i posted.