Method for the bit-wise transmission of luminaire parameters via an interface of an emergency lamp to a readout device, the method having - in an illuminating state of the emergency lamp, generating light visible for the human eye by means of the emergency lamp for the purpose of illumination, - in the illuminating state of the emergency lamp, modulating the light visible for the human eye generated by the emergency lamp for the purpose of illumination, in order to encode the luminaire parameters in the light in a manner invisible for the human eye, - in the illuminating state of the emergency lamp, transmitting the luminaire parameters in a manner so as to be invisible for the human eye in the wavelength range of visible light by means of the visible modulated light, - in the illuminating state of the emergency lamp, pulsewidth modulation of the light by a pulsewidth modulated signal, such that by means of selected duty cycle a medium brightness of the light, which can be generated by a lighting means of the emergency lamp for the purposes of illumination, is set, wherein the pulsewidth modulated signal contains a period (T1, T2, T3) having a pulse with a pulsewidth during a switching on time and a pulse pause during a switching off time, and wherein the pulsewidth of the pulsewidth modulated signal is predetermined for setting the medium brightness of the light, - interrupting the pulse for a first time interval or at most two first time intervals for the purpose of encoding the luminaire parameters, - wherein the first interval is significantly shorter than the predetermined pulsewidth, - transmitting one bit per period (T1, T2, T3) by means of the pulsewidth modulated signal, characterised by - after the culmination of the first time interval or of the at most two first time intervals, continuing the pulse and extending the pulse as far as the first time interval or the sum of the at most two first time intervals, such that the length of the time from the beginning of the pulse as far as the end of the pulse minus the interruptions is equal to the original pulsewidth predetermined for setting the medium brightness of the lamp, and - wherein the maximum pulsewidth is equal to the length of the period (T1, T2, T3) of the pulsewidth modulated signals minus the first time interval or the sum of the at most two first time intervals. - in an illuminating state of the emergency lamp, generating light visible for the human eye by means of the emergency lamp for the purpose of illumination, - in the illuminating state of the emergency lamp, modulating the light visible for the human eye generated by the emergency lamp for the purpose of illumination, in order to encode the luminaire parameters in the light in a manner invisible for the human eye, - in the illuminating state of the emergency lamp, transmitting the luminaire parameters in a manner so as to be invisible for the human eye in the wavelength range of visible light by means of the visible modulated light, - in the illuminating state of the emergency lamp, pulsewidth modulation of the light by a pulsewidth modulated signal, such that by means of selected duty cycle a medium brightness of the light, which can be generated by a lighting means of the emergency lamp for the purposes of illumination, is set, wherein the pulsewidth modulated signal contains a period (T1, T2, T3) having a pulse with a pulsewidth during a switching on time and a pulse pause during a switching off time, and wherein the pulsewidth of the pulsewidth modulated signal is predetermined for setting the medium brightness of the light, - interrupting the pulse for a first time interval or at most two first time intervals for the purpose of encoding the luminaire parameters, - wherein the first interval is significantly shorter than the predetermined pulsewidth, - transmitting one bit per period (T1, T2, T3) by means of the pulsewidth modulated signal, - after the culmination of the first time interval or of the at most two first time intervals, continuing the pulse and extending the pulse as far as the first time interval or the sum of the at most two first time intervals, such that the length of the time from the beginning of the pulse as far as the end of the pulse minus the interruptions is equal to the original pulsewidth predetermined for setting the medium brightness of the lamp, and - wherein the maximum pulsewidth is equal to the length of the period (T1, T2, T3) of the pulsewidth modulated signals minus the first time interval or the sum of the at most two first time intervals.