A fiber optic cassette (10/110/210/310/410/610/810) comprising: a body defining a front and an opposite rear and an enclosed interior , the body further defining a top surface and a bottom surface which define major sides of the cassette body and extend between the front and the rear ; a cable entry location defined in the body for a cable to enter the interior of the cassette (10/110/210/310/610/810), wherein a cable that enters at the cable entry location is coupled to the cassette body and fibers are extended into the cassette body and form terminations at first connectors; wherein the first connectors are connected to a rear side of adapters of an adapter block (40/120/320) located at the front of the cassette (10/110/210/310/610/810), each of the first connectors including a hub and ferrule and each of the adapters including a split sleeve , characterized in that the first connectors are connectors formed of only the ferrule terminating a fiber and the hub directly mounted to and contacting the ferrule , wherein the rear side of each adapter defines a structure for receiving the ferrule and the hub of one of the first connectors; wherein a front side of the adapters define termination locations for cables to be connected to the fibers connected at the rear side of the adapters , the termination locations configured to receive second fiber optic connectors (108/408) having a different format than the first connectors; wherein each second connector (108/408) is a traditional connector such as an SC or LC connector; and wherein the adapters along the front of the cassette body are arranged linearly and extend in a longitudinal direction parallel to the major surfaces defined by the top and the bottom of the cassette body . a body defining a front and an opposite rear and an enclosed interior , the body further defining a top surface and a bottom surface which define major sides of the cassette body and extend between the front and the rear ; a cable entry location defined in the body for a cable to enter the interior of the cassette (10/110/210/310/610/810), wherein a cable that enters at the cable entry location is coupled to the cassette body and fibers are extended into the cassette body and form terminations at first connectors; wherein the first connectors are connected to a rear side of adapters of an adapter block (40/120/320) located at the front of the cassette (10/110/210/310/610/810), each of the first connectors including a hub and ferrule and each of the adapters including a split sleeve , characterized in that the first connectors are connectors formed of only the ferrule terminating a fiber and the hub directly mounted to and contacting the ferrule , wherein the rear side of each adapter defines a structure for receiving the ferrule and the hub of one of the first connectors; wherein a front side of the adapters define termination locations for cables to be connected to the fibers connected at the rear side of the adapters , the termination locations configured to receive second fiber optic connectors (108/408) having a different format than the first connectors; wherein each second connector (108/408) is a traditional connector such as an SC or LC connector; and wherein the adapters along the front of the cassette body are arranged linearly and extend in a longitudinal direction parallel to the major surfaces defined by the top and the bottom of the cassette body . <EOS>