3com MSR 20-20 참조 매뉴얼

dialer timer enable seconds

Dial interface (physical or dialer) view

seconds: Holddown timer value, setting the interval for originating a call to bring 
up a link after it is disconnected. It ranges from 5 to 65535 seconds.

Use the dialer timer enable command to set the link holddown timer.

Use the undo dialer timer enable command to restore the default.

By default the link holddown timer is five seconds

A holddown timer starts upon disconnection of a link. The call attempt to bring up 
this link can be made only after the timer expires. This is to prevent a remote PBX 
from being overloaded.

To leave enough time for a server to call back, the interval between two calls on 
the client need to be at least 10 seconds longer than that of the server. It is 
recommended that the interval on the server be set to 5 seconds (the default) and 
that on the client be set to 15 seconds.

# Set the interval for DCC to make the next call attempt to 15 seconds.

<Sysname> system-view

[Sysname] interface serial 2/0

[Sysname-Serial2/0] dialer timer enable 15 

dialer timer idle seconds

Dial interface (physical or dialer) view

seconds: Link idle-timeout timer, setting the time that a link is allowed to be idle. It 
ranges from 0 to 65535 seconds.

Use the dialer timer idle command to set the link idle-timeout timer.

Use the undo dialer timer idle command to restore the default.

By default the link idle-timeout timer is 120 seconds