It is important to remember that in a digital system all of the units need to be synchronised, thus the need for a common word clock signal feeding all of them. Word clock signal is carried on 75 Ohm BNC cables and at the end of a chain the signal must be terminated by a 75 Ohm resistor to prevent reflections of the signal travelling back down the chain. The Octopre word clock input is terminated with a 75 ohm resistor which is a problem if it is not the last device in the word clock chain.
It is possible to connect a BNC T-Piece to the word clock connector of an Octopre so that the word clock signal routed to it can then be routed to another device, however the 75 Ohm terminating resistor will need to be removed. Below are pictures showing where the terminating resistor (labelled R98 on the board) is on the Octopre ADC board.
If you require the terminating resistor in your Octopre to be removed then you can contact the distributor for your country for more info (visit the distributors page for contact details).
You may wish to purchase a 75 Ohm BNC terminator for the Octopre whose terminating resistor has been removed. If connected to one of the T-Piece junctions it allows the Octopre to still be used as the last device in a word clock chain.