Communications System Owner Manual

ELECTRONIC TANDEM NETWORK (ETN) THROUGH THE ETN AND PNA PACKAGES 5-11
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SO
(6)
592-3456
SO
(1)
8-592-3456
SDN
DIRECT
ACCESS
PNI
3456
592
ETN
(2)
592-3456
(5)
ROUTE
CALL
AT&T SDN
(4)
BILLING &
ROUTING
INSTRUCTIONS
(3)
DATA BASE
QUERY
NCP
ACP ACP
Figure 5-6. Call Flow SDN - to - ETN
4. The ACP updates any pertinent billing records.
5. Based upon the information it received from the NCP, the ACP routes the call to the egress ACP (a
4ESS). Before routing the call, the egress ACP may alter the called number to conform to the ETN
dial plan.
6. The destination ETN receives the call, and routes it to the switch indicated by the RNX. The
destination switch rings the terminal indicated by the extension number it receives.
Call Routing — ETN to SDN
To route ETN calls to non-ETN locations through SDN, the following steps occur (see figure 5-7):
1. At a main switch, the caller dials the 7-digit (RNX-XXXX) or 10-digit (NPA-NXX-XXXX) number
of the destination terminal.
2. The main passes the destination terminal number to the ETN tandem for routing.
3. The tandem passes the 7- or 10-digit destination terminal number onto the AT&T serving office,
which forwards the call onto the nearest ACP.
4. The ACP queries the NCP database, which returns the routing number.
5. The ACP updates any pertinent billing records.
6. Based upon the information it received from the NCP, the ACP changes the destination terminal
number (if necessary) and routes the call to the egress ACP.