Besides the automatic positioning, beaconing, and query response messages, YAAC can also transmit explicit messages to other APRS stations several ways:
Free-text messages can be entered in the messaging area at the bottom of the map window:
or from the Message menu at the top of the map window. Note that if you message a station who is associated with one or more of your security keys, YAAC will ask if you want to digitally sign your message with one of those keys (and ask which key if more than one is associated with the other station).
The menu also provides an option for a chat session window if you wish to carry on a multi-message conversation with another station.
The Chat session begins with a dialog asking what other station you would like to chat with; either select a station already known to YAAC, or type in the callsign of any APRS station, or the alias of a server requiring multiple messages (such as the EMAIL server).
The Chat window then appears. The upper scrolling area contains the history of messages exchanged; the lower area is a place to type in messages to send to the other party.
The WinLink message window allows you to compose a small text-only e-mail message to be sent through the APRSLink gateway to WinLink 2000.
Note that, due to the non-guaranteed delivery of the AX.25 UI frames used by APRS, it is not guaranteed that your message will be delivered (although you should receive an acknowledgement if it does get through). Also, the various lines of the message may be received in duplicate by the APRSlink gateway, causing duplicated text in the delivered message; YAAC does try to ensure the lines are sent in order.