So, what does this actually do then?
From Help:
MSDN/DPNSS Description MSDN/DPNSS is a digital signaling system that provides many other features and is used within a private network of systems.
MSDN/DPNSS Signaling SchemeA digital signaling scheme is used within the private network to pass call information between the system nodes in the network. MSDN/DPNSS uses common-channel signaling (CCS). In this scheme, the signaling information for a number of traffic channels is passed as messages over one channel on a multi-channel digital link.
MSDN/DPNSS Features List MiVoice Business supports the following MSDN/DPNSS features on IP trunks, XNET trunks, and MSDN/DPNSS trunks:
- Answered Line Identity
- Attendant Individual Trunk Access
- Attendant Serial Call
- Call Failure Display
- Call Forwarding
- Call Hold and Three-Party Working
- Conference Split
- Callback on Busy/No Answer
- Callback with Digit Modification
- Called Line Identity
- Camp-on
- Conference
- Direct Trunk Select from Multiline Telephone Sets
- Distinctive Ringing
- Do Not Disturb
- DPNSS Callback Messaging
- DSS/BLF
- Gateway
- Hot Desking
- Interworking
- Last Number Redial
- Loop Avoidance
- Malicious Call Trace
- Meet Me Answer
- Network Attendant Recall
- Network SMDR
- Network Voice Mail - Forwarding Party Info (Subscriber Node)
- Network Voice Mail - Forwarding Party Info (Voice Mail Node)
- Network Voice Mail - Message Waiting
- Network Voice Mail - Message Retrieval
- Override
- Portable Directory Number (Voice Clustering)
- Redirection
- Route Optimization
- Serial Call
- Siemens iSDX DPNSS Interworking
- Stepback
- SMDR
- Tandeming
- Timed Recall
- Transfer to Busy Device
I also remember having to do this a few years ago with MCD 4 or 5 I think. At the time I was told that it helped the controller do call setup earlier/faster that it might otherwise expect to on an inbound call. Where there had been noticeable delays for inbound ringing. But that may have been a completely different issue.