Method (PCD) for setting a quartz watch (MT), the watch (MT) comprising an optical sensor (PR) and a microcontroller (MP) configured to receive electrical signals generated by the optical sensor (PR), the watch (MT) also comprising a point light source (PE) controlled by the microcontroller (MP) of the watch (MT), the method (PCD) being performed by way of a portable electronic appliance (TM) comprising a point light source (EP) and a microcontroller configured to control said point light source (EP), the electronic appliance (TM) also comprising an optical sensor (RP) designed to supply electrical signals to the microcontroller of the electronic appliance (TM), the method (PCD) comprising the following steps: - placing (RGL_PO) the optical sensor (PR) of the watch (MT) facing the point light source (EP) of the electronic appliance (TM) - on the order of the microcontroller of the electronic appliance (TM), flashing (RGL_CL) the point light source (EP) of the electronic appliance (TM) so as to form a sequence of light pulses corresponding to a coding of setting parameters, the sequence then being received by the optical sensor (PR) of the watch (MT) - decoding (RGL_SE) the received light sequence, by way of the microcontroller (MP) of the watch (MT), in order to recover the setting parameters - on the order of the microcontroller (MP) of the watch (MT), setting (RGL_DE) the watch (MT) according to the setting parameters - placing (VRF_PO) the optical sensor (RP) of the electronic appliance (TM) facing the point light source (PE) of the watch (MT) - on the order of the microcontroller (MP) of the watch (MT), flashing (VRF_CL) the point light source (PE) of the watch (MT) so as to form a sequence of light pulses corresponding to a coding of state data characteristic of a current setting of the watch, the light sequence then being received by the optical sensor (RP) of the electronic appliance (TM) - decoding (VRF_SE) the received light sequence, by way of the microcontroller of the electronic appliance (TM), in order to recover the state data - comparing (VRF_CM) the state data with the setting parameters. - placing (RGL_PO) the optical sensor (PR) of the watch (MT) facing the point light source (EP) of the electronic appliance (TM) - on the order of the microcontroller of the electronic appliance (TM), flashing (RGL_CL) the point light source (EP) of the electronic appliance (TM) so as to form a sequence of light pulses corresponding to a coding of setting parameters, the sequence then being received by the optical sensor (PR) of the watch (MT) - decoding (RGL_SE) the received light sequence, by way of the microcontroller (MP) of the watch (MT), in order to recover the setting parameters - on the order of the microcontroller (MP) of the watch (MT), setting (RGL_DE) the watch (MT) according to the setting parameters - placing (VRF_PO) the optical sensor (RP) of the electronic appliance (TM) facing the point light source (PE) of the watch (MT) - on the order of the microcontroller (MP) of the watch (MT), flashing (VRF_CL) the point light source (PE) of the watch (MT) so as to form a sequence of light pulses corresponding to a coding of state data characteristic of a current setting of the watch, the light sequence then being received by the optical sensor (RP) of the electronic appliance (TM) - decoding (VRF_SE) the received light sequence, by way of the microcontroller of the electronic appliance (TM), in order to recover the state data - comparing (VRF_CM) the state data with the setting parameters. <EOS>