Group Call; Urgency Call; Safety Call; Position Request - Standard Horizon SPECTRUM + GX2355S Owner's Manual

9.9.3

Group Call

This feature allows the user to contact a group or vessels capable of using DSC to
automatically switch the radios to a desired working channel for voice communication.
9.9.4

Urgency Call

This call should be used when a vessel may not be truly in distress, but have a
potential problem that might lead to a distress situation.
9.9.5

Safety Call

Used to transmit boating safety information to other vessels. This message usually
contains information about an overdue boat, a derelict afloat, loss of a navigation aid
or an important meteorological message.
9.9.6

Position request

Used to poll another vessel position via DSC and show it on the LCD of the radio.
9.9.7

Telephone Call

Used to automatically place a telephone call through a shore based telephone
company. (In the U.S. market contact maritel at 1866 - marinet for subscription details)
9.10 ADDITIONAL DIGITAL SELECTIVE CALLING
INFORMATION
For additional information the USCG has an excellent site that should be visited at
www.navcen.uscg.mil/marcoms/gmdss/dsc.html

9.11 ABOUT VHF RADIO

The radio frequencies used in the VHF marine band lie between 156 and 158 MHz
with some shore stations available between 161 and 163 MHz. The marine VHF
band provides communications over distances that are essentially "line of sight" (VHF
signals do not travel well through objects such as buildings, hills or trees). Actual
transmission range depends much more on antenna type, gain and height than on
the power output of the transmitter. On a fixed mount 25W radio transmission expected
distances can be greater than 15 miles, for a portable 5W radio transmission the
expected distance can be greater than 5 miles in "line of sight".
page 56 Owner's Manual GX2355S