PSC01 is the X10Pro version of the X10 PF284 Powerflash Module.
It can send an X10 signal on the power line when triggered.
It can be triggered by a dry contact closure from things like a switch or ELK-930 Door Bell Sensor.
Also can be triggered by a low voltage AC or DC voltage. Depending on the Input Switch being set to A or B.
The signals it sends are determined by the Output Mode Switch setting.
You can find the full users manual for it in the Installation section of the X10Pro web site.
http://www.x10pro.com/I have a Powerflash connected to a section of the ELK-930 {has three sections that can be split off the assembly}. Sensing my door bell ringing and sending an X10 signal to some Chime Modules so I know the bell was rung.