RECALLING Article 16(j) of the Convention on the
International Maritime Organization concerning the functions of the Assembly in relation
to regulations concerning maritime safety,
MIND the provisions of regulation 3, chapter IV of the International Convention for the
Safety of Life at Sea, 1974, as amended in 1981,
HAVING CONSIDERED the recommendation made by the Maritime Safety Committee at its
1. ADOPTS the
Recommendation on Performance Standards for VHS Multiple Watch Facilities set out in the
Annex to the present resolution;
Governments to ensure that shipborne equipment fitted with VHF multiple watch facilities
conforms to performance standards not inferior to those specified in the Annex to the
* Some Administrations do not consider that the scanning facility will satisfy their
national VHF watch requirements when a ship is participating in a system operating
pursuant to regulation 18 of chapter V of the 1974 SOLAS Convention.
Annex Performance standards for VHF multiple watch facilities
VHF radiotelephone equipment having multiple watch
facilities should, in addition to meeting the applicable operational standards for VHF
radiotelephone installations, comply with the following performance standards.
2.1 The equipment should include a provision
for the automatic scanning of a priority channel and one additional channel only.
2.2 The priority channel is that channel which
will be sampled even if there is a signal on the additional channel and on which the
receiver will lock during the time a signal is detected.
2.3 The additional channel is that channel which will be
monitored during the periods the equipment is not sampling or receiving signals on the
2.4 Provision should be
included to switch the scanning facility on and off by means of a manually operated
control. In addition it should be ensured that the receiver remains on the same channel
as the transmitter for the entire duration of any communication with the ship, e.g. the
scanning facility could be switched off automatically when the handset is off its hook.
2.5 Selection of the additional channel
and, if provided, of the priority channel should be possible at the operating position
of the receiver or transceiver. If selection of the priority channel is not provided,
the priority channel should be channel 16 unless an Administration considers that an
alternative channel should be watched in a particular area.
2.6 When the scanning facility is in operation, the channel
number of both channels on which the equipment is operating should be clearly indicated
2.7 In a transceiver,
transmission should not be possible when the scanning facility is operating. When the
scanning facility is switched off, both transmitter and receiver should be tuned
automatically to the selected additional channel.
2.8 A transceiver should be provided with a single manual control (e.g.
push-button) in order to switch the equipment quickly for operation on the priority
2.9 At the operating position of a
transceiver the selected additional channel should be clearly indicated as being the
operational channel of this receiver.
3.1 When the scanning facility is switched
on, the priority channel should be sampled with a sampling frequency of not less than
once per 2 seconds. If a signal is detected on the priority channel the receiver should
remain on this channel for the duration of that signal.
3.2 If a signal is detected on the additional channel the
sampling of the priority channel should continue, thus interrupting the reception on the
additional channel for periods as short as possible and not greater than 150
milliseconds. The design of the receiver should provide for its proper functioning
during the period the priority channel is sampled since the receiving conditions on the
priority channel may differ from those on the additional channel.
3.3 In the absence of a signal on the priority channel and during
reception of a signal on the additional channel, the duration of each listening period
on this channel should be at least 850 milliseconds.
3.4 Means should be provided to indicate the channel on which a signal is