Despite being a bit of an outdated system, mariners today still use the MF/HF radio to send Telex, SITOR, or NBDP text messages to one another and to shore stations. One of the more common uses for this system is sending weather broadcasts to NOAA. Nonetheless, we are still tested for this competency on the Mate's Exam, so it couldn't hurt to know it. Here's how you send a message of any kind via telex. (Note: These instructions are specifically written for use with the Sailor Telex system, though can be adapted easily for use with other systems.)

1: Ensure the MF/HF radio is in the TELEX mode as opposed to the Telephony mode used for normal radio contact.
2: Ensure that your TELEX monitor is turned on and that you have a printer connected and powered on.
3: For this model, from the Default Screen, pressing F3 brings you to the Transmit Screen. Here, the methods part ways.

For an Automatic Transmission or Auto Tx, which is the default, you must have a Subscriber set up before taking any further steps.

To set up a Subscriber:
-From the Default Menu, enter the Subscriber Screen as designated by one of the F keys at the bottom of the screen
-Using the SELCAL number of the station you are trying to reach and the frequency you would like to use, complete the Subscriber form.

For an AUTO TX:
-Message type will be either Temporary or previously Saved
-Select either the Coast Station you are seeking from the list provided or a F2 for a list of subscribers you have previously entered.
-Operation:
-Transmit Message
-To Radio Directly
-Through Coast Station
-Call For Conversation
-Coast Station: If Store-and-Forward is previously selected
-Channel: Preset frequency associated with subscriber or station
-Transmit

For a MANUAL TX:
-Call Code:
-SELCAL or Radio Telex No.
-Channel Type:
-Select either Channel or Frequency mode manually
-Enter Channel or Frequency designation
-Transmit

Note: You will be required to listen on selected frequency prior to TX to ensure it is not in use. MANUAL TX mode allows for direct transmission to another station, meaning that as you type, it is directly transmitted to the station rather than writing out the whole message and transmitting all at once. If you are transmitting to a Shore Station, you can communicate with the Station Computer through certain key commands.
HELP+ brings up a list of commands. These commands put the computer into different modes. For example, AMV+ lets the computer know that you will be sending an AMVER message.
Texting KKKK is equivalent to saying "OVER" by telephony, it lets the computer know that you are done submitting and are waiting for a response.
Texting BRK+ breaks communication with the computer entirely.