Operating instructions

Through Mode
Through mode is the default operating mode. The RMC routes every character
of data between the internal system COM1 port and the active external port, or
the 9-pin modem port. If a modem is connected, the data goes to the modem.
The RMC filters the data for a specific escape sequence. If it detects the escape
sequence, it enters the RMC CLI.
Figure 6–1 illustrates the data flow in Through mode. The internal system
COM1 port is connected to one port of the DUART chip, and the other port is
connected to a 9-pin external modem port, providing full modem controls. The
DUART is controlled by the RMC microprocessor, which moves characters be-
tween the two UART ports. The escape sequence signals the RMC to enter the
CLI. Data issued from the CLI is transmitted between the RMC microprocessor
and the active port that enters the RMC.
In through mode, the RMC also outputs it’s powerup messages as well as fatal
errors through the COM1 port.
NOTE: The internal system COM1 port should not be confused with the exter-
nal COM1 serial port on the back of the system. The internal COM1
port is used by the system software to send data either to the COM1 port
on the system or to the RMC modem port if a modem is connected.
Remote Management 6-5