C142 SAFETY OF LIFE AT SEA 



I 



application of the requirement for the device in the case of existing instal- 

 lations for a period not exceeding three years from the date of coming into 

 force of the present Convention. 



(e) The device required by paragraph (d) of this Regulation shall comply 

 with the following requirements: — 



(i) The tolerance of the frequency of each tone shall be ± 15 per cent.; 



(ii) The tolerance on the duration of each tone shall be ±50 milliseconds; 



(iii) The interval between successive tones shall not exceed 50 milli- 

 seconds; 



(iv) The ratio of the amplitude of the stronger tone to that of the weaker 

 shall be within the range 1 to 1-2. 



(/) The receiver required by paragraph (a) of this Regulation shall be 

 capable of receiving the radiotelephone distress frequency and at least one 

 other frequency available for maritime radiotelephone stations in the bands 

 between 1,605 kc/s and 2,850 kc/s, using the class of emission assigned by 

 the Radio Regulations for these frequencies. In addition the receiver shall 

 permit the reception of such other frequencies, using the class of emission 

 assigned by the Radio Regulations, as are used for the transmission by 

 radiotelephony of meteorological messages and such other communications 

 relating to the safety of navigation as may be considered necessary by the 

 Administration. The receiver shall have sufficient sensitivity to produce 

 signals by means of a loudspeaker when the receiver input is as low as 

 50 microvolts. 



(g) The receiver used for maintaining watch on the radiotelephone 

 distress frequency shall be preset to this frequency, or so arranged that setting 

 to the frequency may be carried out in a rapid and precise manner and that, 

 when set to this frequency, the receiver shall not easily be detuned acci- 

 dentally. The Administration may delay the application of the requirements 

 of this paragraph in the case of existing installations for a period not exceed- 

 ing three years from the date of coming into force of the present Convention. 



(/;) To permit rapid change-over from transmission to reception when 

 manual switching is used, the control for the switching device shall, where 

 practicable, be located on the microphone or the telephone handset. 



(/) While the ship is at sea, there shall be available at all times a main 

 source of energy sufficient to operate the installation over the normal range 

 required by paragraph (c) of this Regulation. If batteries are provided they 

 shall under all circumstances have sufficient capacity to operate the transmitter 

 and receiver for at least six hours continuously under normal working 

 conditions.* In installations in cargo ships of 500 tons gross tonnage and 



* For the purpose of determining the electrical load to be supplied by batteries required to 

 have six hours reserve capacity, the following formula is recommended as a guide: 

 A of the current consumption necessary for speech transmission 

 -r current consumption of receiver 



-f current consumption of all additional loads to which the batteries may supply energy 

 in time of distress or emergency. 



Ch. 4 



