Skanti TRP 9250, Technical Manual, Page: 240 / 289

RECEIVING A DIRECT-DIAL CALL, INFO
Direct-dial calls are used for direct telephone dialling of the ship by a land subscriber through an
appropriate coast station providing automatic connection with the public switched telephone network.
If incomming telephone calls cannot be answered for a period, the automatic acknowledgement status
of the DSC 9000 should be changed to ’Unable to comply with telephony calls’. In this case the
acknowledgement will contain the message ’Unable to comply’, and the coast station will after receipt
of that message transmit a busy signal to the calling subscriber.
The coast station evaluates the working channel quality during the DSC call. If quality is satisfactory
the acknowledgement contains the same working frequencies. The coast station then starts dialling
the subscriber.
If the working channel quality evaluation indicates that quality is not satisfactory the coast station may
suggest other working frequencies. In this case the DSC calls are repeated on the new working
frequencies.
If the working channel quality evaluation again indicates that quality is not satisfactory and no other
channels are available the coast station sends an acknowledgement indicating -Cannot use Channel-.
DSC OPERATION RECEIVING A DIRECT-DIAL CALL, INFO
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