Document ID: chunk:federal_register_of_legislation:F2022C01070:body:0:p20
Version: federal_register_of_legislation:F2022C01070
Segment Type: other
Provision Reference: 
Character Range: 53163–56038

be activated not more than 10 times within the same activation period of the AS.
 In this case the activation period shall be limited by the authorised unsetting of the system as a result of the vehicle user's action.
 Some kinds of additional sensors, e.g. passenger compartment control (ultrasonic, infrared) or inclination sensor, etc. ..., may be intentionally deactivated. In this case, separate deliberate action must be taken each time before the AS is set. It must not be possible to deactivate the sensors while the alarm system is in a set state.
18.1.2. Safety against false alarm.
18.1.2.1. It shall be ensured that the AS both in set and unset conditions, cannot cause the alarm signal to sound unnecessarily, in the event of :
 an impact on the vehicle : test specified in paragraph 7.2.13.;
 electromagnetic compatibility : tests specified in paragraph 7.2.12.;
 reduction of battery voltage by continuous discharge : test specified in paragraph 7.2.14.;
 false alarm of the passenger compartment control : test specified in paragraph 7.2.15.
18.1.2.2. If the applicant for approval can demonstrate, e.g. by technical data, that safety against false alarm is satisfactorily ensured, the technical service responsible for conducting approval tests may not require some of the above tests.
18.2. Audible alarm
18.2.1. General
The warning signal shall be clearly audible and recognisable and shall differ significantly from the other audible signals used in road traffic.
In addition to the original equipment audible warning device, a separate audible warning device may be fitted in the area of the vehicle which is controlled by the AS, where it shall be protected against easy, rapid access by persons.
 If a separate audible warning device according to paragraph 18.2.3.1. below is used, the original equipment standard audible warning device may additionally be actuated by the AS, provided that any tampering with the standard audible warning device (generally more accessible) does not affect the operation of the additional audible warning device.
18.2.2. Duration of the audible signal
Minimum : 25 s
Maximum : 30 s.
 The audible signal may sound again only after the next interference with the vehicle, i.e. after the above-mentioned time span.
 (Restrictions : see paragraphs 18.1.1. and 18.1.2. above).
 Unsetting of the alarm system shall immediately cut the signal.
18.2.3. Specifications concerning the audible signal.
18.2.3.1. Constant tone signal device (constant frequency spectrum), e.g. horns : acoustical, etc... data according to ECE Regulation No. 28, Part. I.
 Intermittent signal (on/off) :
 Trigger frequency   (2 ± 1) Hz
 On time = off time ± 10 %
18.2.3.2. Audible signal device with frequency modulation :
 acoustical, etc... data according to ECE Regulation No. 28, Part I but equal pas-sage of a significant frequency range within