Outgoing call number processing
A SIP user may enter a full URI (e.g. email@example.com), an ordinary telephone number or an extension number, when wanting to dial someone. This section determines the interpretation of the entry and the action taken.
Route numbers starting with - If an operator does the processing of dialled numbers, e.g. for connecting to ordinary telephones, this setting can be used instead of the Dial Plan. A SIP address, a domain name or an IP address may be specified in the operator account field. One or several prefixes (separated by space or comma) can be specified. Leaving the prefix field empty, means that all outgoing calls will be routed to the specified operator. The Dial Plan must be OFF or in FB mode for this setting to be active.
Reserved range for internal numbers - A range for internal "extension" numbers can be defined here. (Each individual internal number must be entered in the SIP Account table.) Numbers within this range will not be processed in the Dial Plan table.
Emergency number - One or several numbers (separated by space or comma), e.g. "911 112" can be specified here to directly route emergency calls to a local gateway. The gateway is specified by its domain name or IP address. When this product is equipped with a telephone line port (FXO port), its default name "localgw" is entered so it will be used for the emergency calls. You can select for which SIP clients the routing will be used:
- "Local phones" means telephones connected to any FXS ports on this product.
- "All inside phones" means any local phone and any SIP phone or soft SIP client on the LAN.
- "All phones" means all SIP clients using this product, including remote users registered to this product.
- "None" means this emergency routing is not used.
The Dial Plan will process an entered telephone number and take the appropriate action - e.g. forward the call to a PSTN gateway - according to rules entered. Running the Dial Plan wizard at the web page you reach by the "View/Get Example" link below, will create a Dial Plan that you thereafter can modify for specific needs.
The Dial Plan can be turned On, Off or used in fallback (FB) mode. In fallback mode, the dial plan is inactive unless the WAN connection down or a particular SIP Server to be routed to is out of order. As a backup, the Dial Plan then becomes active.
The Dial Plan requires the SIP Switch option. Press the "Buy" link above the Dial Plan table to buy it or press the "Evaluate" link to make the SIP Switch functional for your testing!
Dial Plan Table - A dialled number is matched against the three first columns in the table, Prefix, Head and Tail. If a match is found, the Action is performed; else the next row in table is checked for a match. The processing order is from top down, until a match is found.
Prefix - The characters in the Prefix+Head+Tail field are compared against the dialled number. The characters in the Prefix field (e.g. 0 for an outside line or * for some special service) must be an exact match to the beginning of the dialled number and are stripped off before an Action is taken.
Head - The Prefix+Head field must also be an exact match to the beginning of the dialled number.
Tail - The Tail field specifies the characters that are allowed in the remainder of the dialled number (after an exact match of Prefix+Head).
Minimum Tail - If, after a match in the three previous fields, the length of the tail part is less than specified in this field, the dialled number is regarded as incomplete.
Action - This field specifies the action(s) that should be performed after a dialled number has been matched by the previous fields.
- "Allow" means that the SIP URI is used as is.
- "Forward" means that the number is sent (as a SIP user name) to the domain specified in the "Forward to" field (typically used for routing calls for an ordinary telephone, to a PSTN gateway).
- "Enum" results in a request to find whether a SIP address exists for the particular number. If a SIP URI is found, the call is forwarded to that URI.
- "Force" means that the call is forwarded to the domain specified, irrespective of from where the call originated (e.g. used for emergency calls).
- "Deny" means that the call will be rejected (e.g. used for too short numbers).
- "A&" before an action instructs this proxy to Authenticate (check user id and password) before the action is performed.
When two actions are specified, the second is performed if the first fails.
Forward to - Normally, the domain name or IP address of the PSTN gateway to which a call shall be forwarded to is specified here. However, you can also specify a SIP user that has an account with a SIP service provider, in which case all users of this product can use that account as a gateway to the ordinary telephone network! (The correct account type has to be set up in SIP Account table.) The dialled number, stripped from the Prefix and preceded by the new Add Prefix Forward in the next column, is passed on as the SIP user name. If there are several entries (separated by space or comma), the next will be tried if the first fails. If the Action is Forward, but nothing is specified in this field, the Default PSTN Gateway specified below this column will be used.
Add Prefix Forward - This prefix will be added in front of the dialled number before the call is forwarded. It may, e.g. be used for adding a country or an area code before sending the dialled number to a gateway.
Add Prefix Enum - This prefix will be added in front of the dialled number before an Enum lookup is done. Typical usage is for adding country code, since Enum uses the full E.164 number.
Enum Root - In the public Enum service, the root is ".e164.arpa". However, for local use or testing, other roots may be used. You can also add several roots (separated by space or comma), that each will be searched until a SIP address is returned. Last, preceded by an exclamation mark, you may also add a root for searching a directory with entries that shall NOT be forwarded to a gateway. Thus, if an entry is found in e.g. the "!nopstnphone.com" root, the call will NOT be forwarded, thus avoiding the risk for loops. The dialled number, stripped from the Prefix and preceded by Add Prefix Enum in the previous column (in reverse order and with dots between each digit) will precede each root searched in the Enum DNS lookup.
Default PSTN Gateway - The domain or IP address entered here will be used if the Action is forward, but no Forward to address is entered. You may also specify a SIP user that has an account with a SIP service provider as described above under the "Forward to" field. If more than one domain is entered (separated by space or comma), the next will be tried if the first fails.
Since the order in which the rows comes in the Dial Plan table is of importance, there are radio buttons to mark a particular row, and a Move button to move a row before another specified row.
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