Spec Sheet Preview: The JK300A Monitor Call Interface is for use in applications where a simple interface is needed to connect the 'monitor' input of an IR300 series or IR400-P5 series station to an external dry contact closure. The JK300A will accept a standard 1/4" phono type plug input and will register a 'MONITOR' call, if plug is removed, or if the 'normally open' dry contact closure is activated (closed). A 1/4" 'dummy plug' is included for use when the monitor point is not connected to an external device. The JK300/2 …