The client-server connection is a standard encrypted TCP connection that remains active for the duration of the client's participation in the IM network. As long as the client is connected to its server, it is able to send and receive instant messages. Because the connection is encrypted, mobile users will be able to safely connect to their servers even when the the connection path between the client and server is unsecure.
All data is exchanged as 7-bit ASCII text for the duration of the connection. (As will be demonstrated later, however, this does not mean that ODSIMS is incapable of transmitting binary data.) Each line of text, which is terminated by CR-LF, is treated as a single transmission unit.