Dsr (Data Set Ready); Dcd (Data Carrier Detect) - Lantronix SCS Reference Manual

Ports

8.12.1 DSR (Data Set Ready)

8.12.1.1 DSR for Automatic Logouts
An SCS port can be configured to automatically log itself out when DSR is no longer asserted; in other
words, the port will log out when the modem is disconnected. This can help ensure port security; users will
be prevented from unplugging terminal lines and using sessions that are still active. See Automatic Logouts
on page 8-11 for more information.
8.12.1.2 DSR for Controlling Remote Logins
The DSR signal can also be used to determine whether or not a remote login to a port will be permitted.
When enabled, the Signal Check characteristic will require the assertion of the DSR signal before a remote
login is permitted on a particular port.
Signal check is generally enabled for use with printers; if the printer doesn't assert the DSR signal, it's
assumed to be disconnected or powered off. In this case, the remote login isn't permitted, and print jobs are
not sent from the SCS to the printer.
To enable Signal Check, use the following command:
Local>> DEFINE PORT 3 SIGNAL CHECK ENABLED

8.12.2 DCD (Data Carrier Detect)

The DCD signal is asserted by the local modem when it detects a connection from a remote modem. If
you're using a DB25 port, no wiring is required in order to use the DCD signal.
Figure 8-51: RJ45 Serial Signals
RTS (output)
DTR (output)
TxD (Transmit Data)
Tx (Transmit Ground)
SCS
Rx (Receive Ground)
RxD (Receive Data)
DSR or DCD (input)
CTS (input)
Figure 8-52: Enabling Signal Check
8-21
Serial Signals
Modem