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Configuration
Serial Port Configuration
4-9
To switch between flow control methods, use the Change Flow Control command
followed by the preferred method. If you do not wish to use flow control at all, specify
None.
Figure 4-19: Enabling Recommended Flow Control
If you’re using XON/XOFF flow control, the XON/XOFF characters will be removed from
the data stream by default. To prevent this removal, enable the Passflow option. However,
passflow is unnecessary in most situations. See Change Flow Control in the Device Server
Reference Manual for more information.
4.3.6 Modems and Modem Signaling
The following sections explain some of the MSS options that are typically considered to be
modem-related. They do not apply exclusively to modems, but to communications devices
in general. Most options are mutually exclusive when enabled.
Note:
Modem Emulation Mode, in which the MSS acts like a modem and only
accepts AT modem commands, is discussed in Chapter 5.
After configuring modem-related settings, refer to the Modem Configuration Checklist on
page B-4.
4.3.6.1 Modem Control
If a connection has ended, the MSS should be able to log out the port and prepare to accept
a new connection. Similarly, if no connection is open, the MSS should know to ignore
spurious characters from the port and only accept valid connection attempts. The MSS can
do both of these when modem control is enabled. Modem control implies three things:
◆
The MSS will log out the port when DSR is dropped (DSRLogout enabled).
◆
The MSS will hold DTR low for approximately 3 seconds after the port is logged
out.
◆
Autostart will not happen until the attached device asserts DSR.
To enable modem control, enter the Change Modem Control command.
Figure 4-20: Enabling Modem Control
Local>> CHANGE FLOW CONTROL CTS
or
Local>> CHANGE FLOW CONTROL XON
Local>> CHANGE MODEM CONTROL ENABLED