The TSCON command will connect to another active or disconnected session. When you connect to another session, you are disconnected from your previous session.

NOTE: See How do I use the TSDISCON command to disconnect a Windows 2000 Terminal Services session, and subsequently reconnect, without loss of data in the running programs?

When you open a CMD prompt and type TSCON /?, you receive:

Attaches a user session to a terminal session.

<b>TSCON \[sessionid | sessionname\] \[/SERVER:servername\] \[/DEST:sessionname\] \[/PASSWORD:pw\] \[/V\]</b>

  <b>sessionid</b>          The ID of the session.
  <b>sessionname</b>        The name of the session.
  <b>/SERVER:servername</b> The name of the Terminal server to connect to (default is current).
  <b>/DEST:sessionname</b>  Connect the session to destination sessionname.
  <b>/PASSWORD:pw</b>       Password of user owning identified session.
  <b>/V</b>                 Displays information about the actions performed.
NOTE: To connect another user's session, Full Control permission is required.

Example:

Open a CMD prompt and type query session. You will receive a display like:
SESSIONNAME   USERNAME        ID      STATE    TYPE    DEVICE
 console      administrator       0   active   wdcon  
 rdp-tcp                      65536   listen   rdpwd
>rdp-tcp#1    user1               1   active   rdpwd
 rdp-tcp#2    user1               2   active   rdpwd
 rdp-tcp#3    user2               3   active   rdpwd
 rdp-tcp#4    user3               4   disc     rdpwd  
 rdp-tcp#5    user1               5   disc     rdpwd
                                  6   idle
                                  7   idle
where rdp-tcp#1 is the current session, session ID 1, owned by user1.

To connect to session 2, type tscon 2 /v, which will return Connecting sessionID2 to sessionname rdp-tcp#1.

To connect to session 1, from session 2, type tscon 1.

To connect to session 5 to session 2, from session 1, type tscon 2 /v /dest:rdp-tcp#5, which will return Connecting sessionID2 to sessionname rdp-tcp#5. Session 2 is connected to session 5, and session 5 is disconnected.

To connect to session 4, owned by user3, type tscon 4 /password:User3Password. Your current session will disconnect and you will be connect to session 4.