Serial Port Configuration
Configuration
4-10
4.3.6.2 Signal Checking
When signal checking is enabled, the MSS will check for the presence of an asserted Data
Signal Ready (DSR) input signal before allowing incoming network connections to the
serial port. Network connections to the serial port will not be permitted unless the DSR
signal is asserted.
To enable DSR signal checking, use the Change Signal Check command.
Figure 4-21: Enabling Signal Checking
4.3.6.3 DSRLogout
When a connection is lost, the MSS should log out the port and close any sessions. If it does
not do so, security problems may result.
When a device connected to the MSS is disconnected or powered off, the DSR signal is
deasserted. The MSS can be configured to automatically close the network connection to a
port when this occurs using the Change DSRLogout Enabled command. This also
prevents users from accessing other sessions by switching physical terminal lines.
Figure 4-22: Enabling DSRLogout
4.3.6.4 DTRWait
Spurious characters from the attached serial device may be interpreted as a login attempt,
which could cause the port to be unavailable for network connections. To avoid this
behavior, the MSS uses the Data Transmit Ready (DTR) output line to signal the serial
device that a connection is possible and acceptable.
Normally DTR will be asserted when the port is idle. The DTRWait feature keeps the MSS
from asserting DTR until the port is actually in use (whether due to a login or a network
connection). To control DTRWait, use the Change DTRWait command.
Figure 4-23: Enabling DTRWait
When DTRWait is enabled, the MSS will assert DTR when a connection begins and de-
assert DTR when the connection ends.
Local>> CHANGE SIGNAL CHECK ENABLED
Local>> CHANGE DSRLOGOUT ENABLED
Local>> CHANGE DTRWAIT ENABLED