IBM F50 RS/6000 7025 - Manual (Page 118)

When Console Mirroring is enabled, the Service Processor sends information to
both serial ports. This capability may be enabled by local or remote users. This
provides local users the capability to monitor remote sessions. Console mirroring
may be enabled for the current session only. For more information, see “Console
Mirroring” on page 4-32.
Start Talk Mode
In a console mirroring session, it is useful for those that are monitoring the
session to be able to communicate with each other. Selecting this menu item
activates the keyboards and displays for such communications while console
mirroring is established. This is a full duplex link, so message interference is
possible. Alternating messages between users works best.
4-10 IBM RS/6000 7025 F50 Series User's Guide