Call Rules

When adding trunks (accounts), you can add call rules for both inbound and outbound calls.

• The inbound rules are used for incoming calls. Defines how calls via an externally reachable phone number are routed to internal extensions, e.g. which users or which teams should be called.
• Outbound rules determine which CallerID should be signalised / transmitted to the callee when called from a specific extension.

When editing and saving a trunk template, two inbound rules plus one outbound call rule will be automatically added.

Inbound Calls

Outbound Calls

Determining the Phone Number Format

Unfortunately, not all providers transmit (signal) the called phone numbers using the same format. This could be the case when:

• inbound calls result in the telephone does not ring on the desired extension.
• outbound calls result the desired number not being signalised to the called party.

Inbound Calls:
If you want to test what exactly your provider is transmitting, simply enter * as your rules' source and destination. This will accept all calls. Log on to the Asterisk CLI (see [Accessing mobydick] ( https://www.pascom.net/doc/en/ “Accessing mobydick”)) and initiate an incoming call. You can end the call as soon as see messages appearing on the Asterisk console, including many debug-related messages. Stop the Asterisk CLI by entering CTRL+C and scroll upwards. towards the top of the log stream, where you will find the following lines:

Verbose("SIP/0991270060-00001cda", "1,destination 0991123456789 is determined")
...
Verbose("SIP/0991270060-00001cda", "1,callee number: 0170123456789")

Under destination you can determine the number format for destination (called) numbers and callee number provides you with the source number format.

Outbound Calls
Should your provider not have provided you with any Signalling Information, you will need to adopt a trial and error approach and test different formats. Possible formats include: with Country Code: 0044; Area Code: 0203; Subscriber number: 12345; Extension: 60):

• +442031234560
• 0442031234560
• 442031234560
• 2031234560
• 02031234560
• 1234560
• 60

Editing Call Rules

In many scenarios, it makes sense to to use a placeholder instead of a set phone number when configuring rules. For example, to add a rule that does not apply to all internal extensions, but rather to group extensions to a rule.
Placeholders are signified by the underscore (_) symbol.

Example:
Should a call rule be required to match all two-digit internal extensions, then the placeholder X is required as follows: _XX

The following placeholders are recognisable to pascom phone systems:

Alongside placeholders, it is also possible to use variables of which the most important are:

• ${CALLERID(num)} the caller’s own number
• ${EXTEN} the original number as dialled by the caller

For example, should the CIDNumber be set to the callers extension number for each outbound call, then you could of course configure a rule for every internal user. However, it is much simpler and quicker to use the ${CALLERID(num)} variable:
For example, if call is coming from the internal extension 11 and the outbound call rule is configured as 020312345${CALLERID(num)}`, then by outbound calls the phone number will be signalised as 02031234511.

Truncating Variables

The variable ${EXTEN} always contains the full number dialled by the caller. If an external call is made to the number 089432111 in an attempt to call the extension 11 from outside of the network, the full number is saved to the variable. If you want to put all incoming calls using the two-digit extension through to the corresponding internal number, you are only interested in using the digits 11 of the string 089432111.

mobydick offers a convenient way to truncate variables. Please see the box below to learn how variables are truncated:

${VARIABLENNAME:Offset:length}

• VARIABLENNAME: Name of Variable, e.g. EXTEN
• Offset: Specifies the length of the variable string that should be skipped before characters are truncated. This offset can also be negative, in which case truncating will begin from the end. The offset is similar to a cursor being moved over the length of the variable
• Length: How many characters should be removed. If nothing is specified, everything up to the end of the string is removed.

Continuing our example, if we want to remove the string 11 from the number 089432111, ${EXTEN:7:2} can be used. This way, the cursor is set after the seventh position in the number and then truncates two digits, those being 11 in our case. The same can be achieved using ${EXTEN:7}, as the variable is truncated at the offset when no length is specified. The easiest way is to use ${EXTEN:-2}. The cursor will then be positioned two characters from the right end, just before 11 and will remove everything to the right.

Clip no screening

CLIP no screening is a feature for outbound calls, which enables a phone number to be transmitted which does not belong to the telephony connection. Within a pascom phone system, CLIP no screening is used to, for example, to signal the phone number of the original caller should a call forwarding to an external number be set e.g. to a mobile phone.

Finally, an outbound rule must be configured: