Instruction manual

Electronic Tandem Network (ETN)
Issue 4 May 2003 139555-233-767
QSIG/DCS voice mail interworking
See ‘‘QSIG/DCS voice mail interworking’’ on page 110.
Electronic Tandem Network (ETN)
In an Electronic Tandem Network (ETN) — also known as Private Network
Access (PNA) — Communication Manager provides a variety of features on a
network-wide basis. It allows calls to other systems in a private network. These
calls do not use the public network. Instead, they are routed over your dedicated
facilities.
Automatic alternate conditional routing
You can control the routing of particular calls using conditional routing. For
example, you can limit the number of communications satellite hops
(communications satellite links used as trunks) in any end-to-end private network
routing pattern. Limiting the number of satellite hops may be desirable for
controlling transmission quality or call delay in both voice and data calls.
Trunk signaling and error recovery
The reliability of electronic tandem network calls is improved by allowing a trunk
call to be retried on another circuit when signaling failures occur.
■ tandem switch: A switch within an ETN that provides the logic to
determine the best route for a network call, possibly modifies the digits
outpulsed, and allows or denies certain calls to certain users.
■ tandem through: The switched connection of an incoming trunk to an
outgoing trunk without human intervention.
■ Tandem Tie-Trunk Network (TTTN): A private network that interconnects
several customer switching systems.
See also, ‘‘Port Network Connectivity (ATM-PNC)’’ on page 122.
Extension number portability
When employees move within the network, they can retain their extension
numbers. The ability to keep extension numbers, and even electronic tandem
network and direct inward dialed numbers, when moving to other locations within
the company eliminates missed calls and saves valuable time.