When used in an expression, the command returns a list with 5 entries:
1. The local port, or NIL if no telnet server is started.
2. TRUE if telnet raw mode is used, else FALSE.
3. TRUE if IPv4 is used, else FALSE.
4. The remote IP, or NIL if no telnet connection is active.
5. The remote port, or NIL if no telnet connection is active.