The ZPCB2252-MSL is the slave PCB which has no loop interface to the CIE but is directly controlled by the ZPCB2252-MML board. Up to 7 slave boards can be daisy chained to the master board and each slave has 32 LED outputs allowing the number of LED outputs to be expanded up to a maximum of 250 (not all LEDs on the 7th slave are used). The power to these additional LEDs is also from the external power supply but is transferred through the interlinking cable between boards.

Please refer to the datasheet for more information.