Polycom ViewStation FX4000 User Manual page 139

© Polycom, Inc. 2002
Chapter 4 - Advanced Configuration for your Network Environment
without notification. Either the upstream switch or PBX is
responsible for:
– Parsing the dialing string
– Interpreting any prefixes or access codes
– Determining whether the call is national or
international
The default value, Unknown, is preferred and should work
in most cases. Unknown should work with all properly
configured PBXs and with most telephone company
switches. One notable exception in North America is an
ATT 5ESS switch, which is provisioned with Accunet, or an
ATT 4ESS switch. For these switches, set the numbering
type to ISDN.
• ISDN: If this option is selected, the numbering plan is
identified to the upstream switch as ISDN, and the number
type, which is either national or international, is determined
from the dialed phone number. If the dialed phone number
starts with the international dialing prefix that is currently
selected, the type is set to the international and the prefix is
removed from the number before the number is sent to the
upstream switch. Otherwise, the number is marked as
national and passed to the upstream switch without
modification.
When ISDN is selected, the international dialing prefix is
not recognized if any other access code or prefix precedes
the international dialing prefix. The phone number must
begin with the international dialing prefix.
International Dialing Prefix—The international prefix defaults
to 011 for North America and 00 for European countries. The
default depends on the country. If you specify a numbering type
or ISDN, the system searches for this value.
Call-by-Call—Call-by-call is a number from 1 to 31, which is
optionally sent to an upstream telephone company switch, if
required. For example, specify a value of 6 for a T1 PRI network
interface module that is directly connected to an ATT 5ESS
switch, which is provisioned with Accunet. You must consult
with the telephone company service provider to determine
whether a call-by-call value is required for a particular PRI line.
141