When composing a new message, you must choose how the message will be sent:

• Winlink Message: Your station makes a radio connection to a Radio Message Server (RMS). The RMS makes an Internet connection to a Common Message Server (CMS) that is the central message repository. Your messages are sent via radio to the RMS and then through the Internet to the CMS until the recipient connects and downloads messages addressed to themselves. This mode is efficient and highly reliable. Winlink operates multiple CMS that synchronize with each other frequently to provide completely redundancy. If an RMS is down and unable to receive a connection, the client can connect to a different RMS. Since all messages are stored in the central CMS database, it doesn’t matter which RMS the sender and recipient connect to.
• Radio-Only Message: Where as the previous mode relies on an Internet connection between the RMS and a CMS, the Radio-Only mode does away with the CMS and the internet connection it relies on. Instead, messages are sent to a designated RMS for storage until it is retrieved by the recipient. This mode of operation can operate with local and total Internet outages.
• Peer-To-Peer Message: This mode of operation transfers messages directly from the sender to the recipient without going through an RMS or a CMS and without the Internet. This is like a “simplex” mode, which requires:
  • Both stations to be on the air at the same time and on the same frequency.
  • Both stations to use the same transmission protocol (Packet, Winmor, Pactor, etc).

So the steps to compose a message are to:

1. Select how the message will be sent as.
2. Enter the recipient's address (usually their callsign, which may or may not require a dash number)
3. And lastly, after the message is written, Post to Outbox, which saves the message locally marks it to be sent.

Before making a connection (section below), it's possible to post multiple messages to the outbox.

The type of connection needed is chosen from the Open Session drop down menu.

• https://winlink.org/content/overview_winlink_hybrid_network