A communication apparatus, comprising: a connection unit that includes a plurality of signal lines and is configured to connect to an external recording device; and control means for controlling communication with the external recording device connected to the connection unit, wherein the control means is configured to perform control to: determine whether a second signal has been input before a predetermined time period elapses since a first signal was output to the external recording device, the second signal indicating that the external recording device is compatible with a second transfer mode; in a case where it is determined that the second signal has been input, perform communication in the second transfer mode; and in a case where it is determined that the second signal has not been input, start first initialization processing for performing communication in a first transfer mode, determine whether the external recording device is compatible with a third transfer mode based on communication in the first transfer mode, and in a case where it is determined that the external recording device is compatible with the third transfer mode, perform communication in the third transfer mode. a connection unit that includes a plurality of signal lines and is configured to connect to an external recording device; and control means for controlling communication with the external recording device connected to the connection unit, wherein the control means is configured to perform control to: determine whether a second signal has been input before a predetermined time period elapses since a first signal was output to the external recording device, the second signal indicating that the external recording device is compatible with a second transfer mode; in a case where it is determined that the second signal has been input, perform communication in the second transfer mode; and in a case where it is determined that the second signal has not been input, start first initialization processing for performing communication in a first transfer mode, determine whether the external recording device is compatible with a third transfer mode based on communication in the first transfer mode, and in a case where it is determined that the external recording device is compatible with the third transfer mode, perform communication in the third transfer mode. determine whether a second signal has been input before a predetermined time period elapses since a first signal was output to the external recording device, the second signal indicating that the external recording device is compatible with a second transfer mode; in a case where it is determined that the second signal has been input, perform communication in the second transfer mode; and in a case where it is determined that the second signal has not been input, start first initialization processing for performing communication in a first transfer mode, determine whether the external recording device is compatible with a third transfer mode based on communication in the first transfer mode, and in a case where it is determined that the external recording device is compatible with the third transfer mode, perform communication in the third transfer mode. start first initialization processing for performing communication in a first transfer mode, determine whether the external recording device is compatible with a third transfer mode based on communication in the first transfer mode, and in a case where it is determined that the external recording device is compatible with the third transfer mode, perform communication in the third transfer mode.