Electronic devices according to various embodiments of the present invention comprise: a connector for communicating serial data to an external electronic device; a nonvolatile memory; and a processor, wherein the processor is configured to: acquire identification information of the external electronic device via the connector; confirm whether or not a designated mode of the external electronic device is supported at least on the basis of the identification information; based on the identification that the external electronic device supports the designated mode, acquire first additional information associated with the external electronic device; based on the identification that the external electronic device does not support the designated mode, acquire second additional information associated with the external electronic device; and store the identification information or at least a part of the second additional information in the nonvolatile memory.