User`s manual
Version 5.4 195 May 2008
SIP User's Manual 3. Web-Based Management
3.4.5.3.2 Numbering Plans and Type of Number
Numbers are classified by their Numbering Plan Indication (NPI) and their Type of Number
(TON). The device supports all NPI/TON classifications used in the standard. The list of
ISDN ETSI NPI/TON values is shown in the following table:
Table 3-43: NPI/TON Values for ISDN ETSI
NPI TON Description
Unknown [0] Unknown [0] A valid classification, but one that has no information
about the numbering plan.
Unknown [0] A public number in E.164 format, but no information
on what kind of E.164 number.
International [1] A public number in complete international E.164
format, e.g., 16135551234.
National [2] A public number in complete national E.164 format,
e.g., 6135551234.
E.164 Public [1]
Subscriber [4] A public number in complete E.164 format
representing a local subscriber, e.g., 5551234.
Unknown [0] A private number, but with no further information
about the numbering plan.
Level 2 Regional [1]
Level 1 Regional [2] A private number with a location, e.g., 3932200.
PISN Specific [3]
Private [9]
Level 0 Regional (local) [4] A private local extension number, e.g., 2200.
For NI-2 and DMS-100 ISDN variants, the valid combinations of TON and NPI for calling
and called numbers include (Plan/Type):
0/0 - Unknown/Unknown
1/1 - International number in ISDN/Telephony numbering plan
1/2 - National number in ISDN/Telephony numbering plan
1/4 - Subscriber (local) number in ISDN/Telephony numbering plan
9/4 - Subscriber (local) number in Private numbering plan
3.4.5.3.3 Mapping NPI/TON to Phone-Context
The 'Phone-Context Table' page is used to map NPI and TON to the Phone-Context SIP
parameter. When a call is received from the ISDN/Tel, the NPI and TON are compared
against the table and the Phone-Context value is used in the outgoing SIP INVITE
message. The same mapping occurs when an INVITE with a Phone-Context attribute is
received. The Phone-Context parameter appears in the standard SIP headers where a
phone number is used (Request-URI, To, From, Diversion).