Configuring general ISDN settings
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Allow parallel
dialing
Parallel dialing allows all ISDN cal ls to
be bonded to be dialed
simultaneously.
Enable parallel dialing if your ISDN
endpoints support it. Since parallel dialing
is not supported by all equipment,
disabling parallel dialing may improve
interoperability with legacy endpoints;
however, call setup times for outgoing
ISDN calls may increase slightly. This
option does not affect incoming ISDN
calls.
Port search
order
Whether free B-channels will be
selected starting with the low-
numbered port and working towards
the high-numbered port, or the other
way around.
When making outgoing ISDN calls,
this setting is used to select which
port to place the call on; when
receiving incoming ISDN calls, it is
used to select which port number to
advertise to the ISDN endpoint.
This order is applied to the ports selected
in the dial plan.
Load
balancing
Use this option to forward calls to
another gateway if all of this ISDN
Gateway's channels are full or
unavailable. Your ISDN network must
support this functionality.
Select Active on its own or in
combination with Use higher
numbered channels only.
When Active is selected, the ISDN
Gateway rejects incoming ISDN calls if not
enough channels are available, and sends
a 'Redirection to new destination' message
to the ISDN network. It is up to your ISDN
network provider to redirect the call to
another gateway.
To work out the number of free B-
channels, if Use higher numbered
channels only is selected, the gateway
considers only higher-numbered channels
than the channel used by the initial call. If
you are unsure whether you need to
enable this option, refer to your ISDN
network provider.
Outgoing
ISDN calls
Select from the drop down list.
When Establish layer 2 is selected, only
layer 1 needs to be up before placing a
call. The ISDN Gateway will attempt to
bring up layer 2.
If Require layer 2 is selected, then layer 2
must be up before calls are allowed. (This
was the default behavior in older software
versions.)
ISDN advanced settings
Field
Field description Usage tips
Specify
national/international
type of number
Some ISDN configurations,
including certain 4ESS switches,
need the ISDN Type of Number
(TON) to be explicitly set to National
If this option is selected, then an
outgoing ISDN call has a National
TON or International TON depending
on whether the beginning of the
dialed number matches the value