Configuring an Asynchronous Port 5-3
General Asynchronous Port Settings
connection can be established to a specified port on the PortMaster. Once the
connection is established, the connected device such as a printer or modem can be
accessed as if it were connected directly to the host.
Ports can also be configured to be accessed by programs using TCP/IP sockets, or by
Telnet from the network.
Chapter 18, “Accessing Shared Devices,” gives an example of sharing devices across a
network.
General Asynchronous Port Settings
Certain settings must be configured for every asynchronous port, regardless of the port
type and configuration you select.
Overriding Certain Port Settings
If you configure a port as a host device, you can specify that the host device can
override certain port settings. This feature allows the host running in.pmd to alter the
active parameters through software control, by using operating system I/O calls (ioctl
calls in UNIX). The settings that the host can override are speed, parity, databits, and
flow control. These settings can be changed by the host using an ioctl() system call. All
overrides are turned off by default. If you want to allow a host to override a port setting,
turn override for the parameter on.
You can override the settings for all asynchronous commands by using the set all
override command.
To turn override on for a particular parameter, use the following command:
Command> set S0|all override xon|rts|speed|parity|databits on|off
Setting the Port Speed
Modern modems should be set to run at a fixed rate. To define a fixed rate, lock the data
terminal equipment (DTE) rate by setting all three speeds to the same value.
You can set the speed for all the asynchronous ports simultaneously by using the set all
speed command.
