Call Rules

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Using call rules you are able to manage which extensions are available over which trunk i.e. who can call out via this trunk. Call rules are automatically added when using one of our trunk templates and can then be modified.

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 Call Rule
Central This rule applies to the first number in your DID number block. In most cases, this will be your central switchboard.
Extension This rule indicates that each internal extension is externally accessible.
Outbound Call Rule
Standard This rule ensures that when making outbound calls, the callers extension number will also be included in phone number signalling.

Inbound Calls

Setting Description
Title Name of the Rule.
Source The caller’s phone number. * means this rule applies to all inbound calls
Destination The number as dialed by the caller.
Extension Displays to which internal extension calls should be routed to.
Language Indicates the channel language for the rule - i.e. in which language callers should hear prompts etc.

Outbound Calls

Setting Description
Title Name of the Rule.
Show in Client As default set to “No”. By selecting “Yes”, mobydick desktop client users will be able to select this call rule from a dropdown list in the client when making outbound calls. Useful scenarios include using multiple numbers or Private Numbers etc.
In-Prefix The prefix dialed to select this call rule e.g “0” or “9”. Could also be “*1” for example. By outbound calls, the In-Prefix will be automatically removed and not dialled
Source Defines for which internal extensions the rule applies. * refers to a rule that applies to all internal extensions.
Destination The actual dialled number, in this case the number your agents are dialling.
CIDNumber The number to transmitted when making outbound calls. To withhold the number, leave it blank.
Out-Prefix The number required to dial another system that requires a dial prefix, i.e. in the migration phase of moving to mobydick from another phone system.
Deny As default set to “No”. Set to “Yes” when you would like top deactive a particular call rule.
PIN Set a PIN for using this particular call rule - useful when adding rules to restricting calls to premium or international numbers.
Transmission Capacity Supported communications media, e.g. Voice, Video etc.
Account Should you have added multiple accounts in your trunk, you can select over which account the outbound call should be routed.

Should you have multiple trunks with the same outbound rules, these must be differentiated using different In-prefixes.
It is highly recommened to utilise a consist strategy for in-prefixes, as deploying rules with and without in-prefixes configured can lead to problems.

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) 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.

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:

Placeholder Description Example
X matches number from(0-9), e.g. _3X is used for the numbers 30 to 39.
Z matches number from 1 to 9.
N matches number from 2 to 9.
. last number is followed by any other number. Example: _0X. matches all numbers starting with 0.
[a-b] single-digit numeric interval. Example: _3[1-5] matches the numbers 31-35.
* any number or or character.
a|b Logical OR disjunction. In this case A or B.

Rule Application (Bestmatch)
Rules are applied according to the relevancy i.e. according to best match, regardless of list order in the table. If several rules match a call, the rule providing the closest match will be chosen. A rule with a very narrow set of criteria will be preferred over a rather loosely defined rule. The order of the rules, has no effect of how rules are applied making future adjustments easier to undertake.

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: 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.

If you want to use Clip no screening, please check with your voice provider whether this function is enabled and / or supported on or connection.

Finally, an outbound rule must be configured:

Example setting Description
Source _XXXXX. The source that is calling has a minimum of 5 digits, meaning it cannot be an internal extension.
CIDNummer ${CALLERID(num)} The number of the original caller