Compatible Systems 5.4 Manuale Utente

This parameter determines whether the interface will source a clock signal or 
expect to receive an external clock.

•

If checked, the interface will expect to source a clock, and will ignore an 
external clock signal.

• If 

unchecked, the interface will expect to receive an external clock. This 

is the default setting.

v Note:  In addition to this setting, some WAN interfaces require internal 
hardware jumpers to be changed in order to source a clock signal. Check the 
Installation Reference Guide for the device.

This pull-down menu determines the speed of the port’s internal clock. In 
Async operation, this value must match the baud rate of the external commu-
nications device. In Sync operation this value is ignored unless Tx Clock 
Internal is checked, in which case it determines the speed of the clock which 
is sourced.

This setting determines the type of flow control used on interfaces set for 
Async operation.

•

If none is selected, the interface will not pace the rate at which it sends 
characters.

• If 

hardware is selected, the interface will use the state of the CTS (Clear 

To Send) line to determine whether characters may be sent. This is the 
default setting.

•

If XOn/XOff is selected, the interface will trap XOn and XOff characters 
to determine whether characters may be sent. This method is also known 
as “software” flow control.

v Note:  You may also need to configure your communications device 
(through switch settings or internal registers) to run with software flow 
control. Software flow control is not recommended at speeds above 9600 
Baud.