GMDSS. FCC Test 55

Which of the following statements concerning SITOR communications is true?

SITOR communications can be used to contact a NAVTEX transmitting station when requesting a repeat transmission of a missed NAVTEX message.
In ARQ, each character is transmitted twice, about 250 milliseconds apart.
In ARQ, the 'information sending station' will transmit a block of three characters that the receiving station will subsequently acknowledge or request be retransmitted.
In ARQ, the 'information sending station' transmits a block of three characters twice, about 250 milliseconds apart.

Which of the following keystrokes or characters follows most commands in ARQ communications when working an automated Coast Station?

The 'ENTER' key.
The go-ahead ('GA') command.
The 'END' key.
The plus ('+') key.

What statement is true regarding the exchange between two parties engaged in SITOR communications?

In ARQ, each character is transmitted twice, with the second displaced in time from the first.
In ARQ, the 'sending' station transmits a block of three characters and the 'receiving' station responds with either a one-character acknowledgement of the receipt of a valid block or a negative acknowledgement indicating that the block should be re-sent. Following this the 'transmitting' station will send a new block or retransmit the previous block, as required.
In ARQ, the 'sending' station transmits a block of three characters and the 'receiving' station responds with a one character acknowledgement. Following this the 'transmitting' station will send a new block.
Broadcasts of Marine Safety Information, traffic lists, etc. can be copied by the receiving station in ARQ mode.

Which of the following is true of SITOR ARQ mode?

This is an interactive mode.
This mode is generally used to broadcast messages.
Each character is transmitted twice.
Each character is repeated three times.

Which of the following keystrokes or characters is sent as part of ARQ communications to switch information transmission control from one station to the other?

The plus and question mark keys ('+', '?').
The 'ENTER' key.
The go-ahead ('GA') command.
The 'END' key.

Of the following, which is true of SITOR ARQ mode direct printing radioteletype transmission?

Each data block consists of three characters.
The acceptance code consists of three characters.
A continuous data stream is transmitted.
Forward error correction reduces the number of errors.

Review Answers

GMDSS. FCC Test 55

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