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 it to be retransmitted .

In ARQ, the "information sending station" transmits a block of three characters twice, about 250 milliseconds apart.

SITOR communications can be used to contact a NAVTEX transmitting station when requesting a repeat transmission of a missed NAVTEX message.