To blow plastic hollow bodies, each mold has its respective compression chamber connected to it, constituted by a cylinder -piston assembly; pressure is initialized in the chamber; the fluid is compressed in the chamber; the chamber is connected with the blank when the piston position attains a predetermined position and chamber volume continues to be reduced to complete the blowing. The fire alarm system includes a current modulation section and an address specification section. According to various embodiments disclosed herein, media content can be shared with a social network, or the like.