UCSB vs. UCBB

[BertZ]

I am in the process of rebuilding my old CNC router. Part of the process is replacing the old motion control system with UCCNC.
I have already purchased a UC300ETH and a UCSB BOB. I now realize that the UCSB has only 5 inputs and I will require 6 and possibly 8 inputs.
Can I just buy another UCSB and plug it into one of the UC300 ports, or must I buy a UCBB

[dezsoe]

The UC300ETH_5LPT has 3 extended and 2 normal ports. The normal ports have 12 outputs and 5 inputs while on the extended port the pins 2 to 9 are also inputs. The UCSB is for a normal port, the UCBB is for a normal and an extended. The CN1 on the UCBB and the UCSB are the normal ports, you can connect them to port 2 and 3 on the UC300. CN2 on the UCBB is the extended port which can be connected to port 1, 4 and 5 of the UC300.