The First documentation says this device is an implementation of the aTinyIR2 device. The schematic for the TinyIR2 shows a PIC controller and implies that the outputs come from some tri-state pins on the controller. As such there is no way to know whether it is safe to "OR" the outputs of several boards together with simple wiring. It might be OK to use diodes but I am not sure it is worth the frustration of trying to troubleshoot two boards and get them working together.
http://www.tauntek.com/TinyIR2-schematic.pdf