Forwarding the original calling number when redirecting a call (CLIP -no screening-) (kb3048)

The information in this article applies to:

  • SwyxWare 2015
  • SwyxWare 2011
  • SwyxWare v7.00
  • SwyxWare v5.00
  • SwyxWare v6.xx, SwyxWare 2013

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Configuration of the Swyxware for CLIP no screening / user provided numbers


If you redirect a call to a public number using SwyxWare, the number which is going to be transmitted to the final destination will be the public number assigned to the SwyxWare and not the number of the caller. In some situations it may be useful / wise to send the telephone number of the original caller and not the one attributed to the SwyxWare. In order to do so, the feature “CLIP no screening” has to be existent.

“CLIP no screening” is a feature of the telephone service provider (TSP) for outgoing calls. Any number pre defined by the user can, hereby, be sent to the destination, in addition to the telephone number of the caller.

“No screening” means in this context, that the number specified by the caller will not be checked for correctness by the telephone network. It can, therefore, be any number that the caller has defined himself.

The standard practice is that both telephone numbers, the one assigned by the TSP as well as the one chosen by the customer, be transmitted into the telephone network. The device-specific settings on the part of the receiver will then decide, which telephone number (or eventually both) to display.

By default CLIP no screening is not activated at the TSP and has to be ordered as an extra service and might cost some fee. Not all TSPs offer this service, in some countries it is not availaible at all.


SwyxWare configuration (please check release version!):

Precondition: ClipNoScreening is activated at the TSP.

For trunks of type "SIP" it is necessary that the SIP provider (ITSP) supports the feature AND the appropriate provider profile is used within SwyxWare, see Overview of tested SIP provider und Configuration and Adaptation of SIP Providers via Provider Profiles (kb3436).



SwyxWare 2011 (v8) and later:

  • Step 1a) Only for trunks of type 'ISDN' (SwyxGate with ISDN boards in the server): Inside the properties of the affected Trunk Group(s) goto Profile, Number Formatting, Conversion for outbound Calls, Calling Party Number and select "Clip no screening".
    This step is not required for other types of trunks (e.g. 'SIP' or 'SIP-Gateway'), please proceed diretly with step 1b).
  • Step 1b) Inside the properties of the affected Trunk(s) goto Number Signalling and select  "Always use originator's number".

SwyxWare 6.xx until 7:

Inside the properties of the affected Trunk Group(s) goto Profile, Number Formatting, Conversion for outbound Calls, Calling Party Number and select "Clip no screening".

SwyxWare 5.x only:

- Modification of the registry key responsible for forwarding the telephone number
The following registry keys exist in each of the branches needed by the controller and have to be modified for each controller for which “Clip no screening” will be configured.
HKEY_LOCAL_MACHINE\Software\Swyx\ IpPbxGate\CurrentVersion\Options\Ctrl"x"

AddPtpSubscriberNumber, REG_DWORD, Value: "1"
AddAreaCode, REG_DWORD, Value: "1"
OutgoingCLITypeAndPlan, REG_DWORD, Value: "0x21"
UserProvidedCLITypeAndPlan, REG_DWORD, Value: "0x41"
UserProvidedCLIScreeningIndicator, REG_DWORD, Value: "0x01

 With this change in the registry key, it will be signaled to the TSP, that the given number is equivalent to the Type "ISDN / E.164 and the number type "national".


The second step in the configuration will be the allocation of the downloadable script rulepreprocessing.vbs, so that in the case of a call diversion, the original number can be transmitted.

SwyxWare 2011 (v8) and later: There is no changed rulepreprocessing script required, skip this step!

SwyxWare 6.1x until 7: The script will have to be copied into the SwyxWare Database (SwyxWare Administration, Server properties, Files, Edit, Add), Scope=Global, Category=Call Routing scripts.

SwyxWare 5.x and 6.0x:  The script will have to be copied into the following directory: \Share\Data\PhoneClient\Scripts.


This script is only obligatory when there are no ECR Licenses available.

In case such ECR Licenses are available, the following variables can be modified in the RulePreProcessing.vbs rule, which will be performed before the connection to the PSTN has been established.
PbxCall.CLIMode = 0 // prefer originating number
PbxCall.CLIMode = 1 // prefer redirecting number (default)

If on a redirected externalcall a custom number (08000/0700) should signaled to the PSTN, the following variables should be conducted in the RulePreprocessing rule.
PbxCall.CallingPartyNumber = "custom number"

Please don’t modify the RulePreProcessing.vbs available for download, this file is protected against modifications without ECR Licenses.

For trunks of type "SIP" it is necessary that the SIP provider supports the performance feature AND the appropriate provider profile is used within the SwyxWare, see xxx


As far as software supplied or used by us, includes open source elements the additional terms under apply in addition. An overview which products from the Swyx portfolio include open source elements and which open source license is relevant can be found under

The third-party contact information included in this article is provided to help you find the technical support you need. This contact information is subject to change without notice. Swyx in no way guarantees the accuracy of this third-party contact information nor is responsible for it's content.


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