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Suggested configuration when using the Dialogic DMG1000 Media Gateway with European Hicom PBXs in a VM/UM/IVR environment.

Issue:
European revisions of Siemens Hicom PBX software do not allow subscribers message waiting indicators (MWI) to be set or cleared from a digital station port. This restricts applications that wish to use digital models of the DMG1000 Media Gateway to connect an IP based voice mail system to their Siemens PBX. 

Solution Summary:
This limitation can be overcome by using an analog DMG1000 Media Gateway, in addition to the existing digital gateways, connected between the PBX and the VoIP media server to perform the setting/clearing of subscriber MWIs. 

Technical Discussion:
A typical installation of a digital DMG1000 Media Gateway allows for the use of the digital station ports between the gateway and the PBX for all types of call traffic (inbound circuit to IP, outbound IP to circuit and message waiting). 

Shown below is a typical installation of a digital DMG1000 Media Gateway in this type of installation.
 

When using a digital DMG1000 Media Gateway to connect to a European Siemens Hicom PBX you need to use an additional gateway as shown below.


The requirement for the additional gateway is because the European variants of Siemens Hicom PBX software do not allow digital station sets to set or clear message waiting lights. This activity is only allowed from analog station ports.

As a result of this required configuration, the voice processing application will need to be configured so that any message waiting requests are sent to the analog DMG1000 Media Gateway only. If the digital gateway receives a request it will attempt to process it and a failure will be returned to the application.

The analog station line extensions used by the analog gateway should not be used to process inbound calls. Inbound calls to these station ports can collide with outbound message waiting requests and cause slowdowns in service so it is suggested that these extension numbers not be made publicly available to any users on the system for this reason.

As of the release of Service Update 4 for the DMG1000 Media Gateway you are allowed to configure each circuit side port of the gateway for a specific set of features, making this configuration more robust. If you are using this updated software it is recommended that you:

• Configure the ports on your digital gateways to ‘calls only’ so that message waiting requests will not be serviced by these ports.
• Configure the ports on the analog gateway to ‘mwi only’ so that inbound calls to these ports will not be serviced.

Please refer to your PBX programming documentation and the documentation for your voice processing system for the correct programming required on those systems.

The only PBX programming requirement for the analog gateway channels are that they have the ability to set sand clear subscriber message waiting lights.

To know if your digital gateway has Service Update 4 please check the following:

• The version page of the web interface will show a version for the ‘Gateway Application’ of 4.0.68 or higher.
• Check to see if the web interface offers you a page called ‘Port Capabilities’.

This configuration is suggested regardless of what VoIP protocol the application is using (ie: SIP or H.323).

Please consult with your voice processing software vendor before upgrading your gateway to Service Update 4 to ensure that they are able to support your use of this revision. 

Glossary of Acronyms / Terms

• SIP ---- Session Initiation Protocol
• PBX ---- Private Branch Exchange
• VM ---- Voice Mail
• IVR ---- Interactive Voice Response