Profile: Design International Ltd. specializes in the design and manufacture of prison & detention center security systems, intercom, Vidicom, cell call, locking, and alarm systems. We also design and manufacture bespoke electronic systems & embedded software development. We have the expertise to design electronic circuits and PCBs, produce mechanical drawings, write low level firmware for micro controllers, design high level windows applications & databases, and manufacture and test small to medium production runs. Our cell call plate is fitted with an optical tamper switch. In the cell call plate, a stainless steel plate is located inside the cell, and the plate can be surface mounted or fitted flush into the wall. The stainless steel push button is used to originate a call. A large reassurance LED and audible tone is activated until the call is reset. Our monitored input module has general alarm input module, and supports 8 fully monitored inputs. Each input is fed with a wetting voltage, and the resulting current flow is monitored to determine the resistance of the external circuit. These resistance values are then averaged and de-bounced, and used to report the state of the alarm input. Our 5 Port hub expansion module provides 5 common ports to allow the interconnection of up to 5 I/O modules. It also includes a RS485 feed/breakout or common connector, and a power feed connector.