Check this box if your ICOM radio is connected to the computer with a full duplex (bidirectional) connection. This is an uncommon situation. When this box is checked, S Meter Lite will not expect to receive the data it sends. Since the CI-V Bus has a single wire for send and receive data, data which is sent by the computer is redirected back to the computer. In very special cases, this is not true, and S Meter Lite should not expect to receive the data that it sends. In those rare cases, check this box.