Lucent Technologies MERLIN LEGEND Release 6.1 Feature Reference page 725

MERLIN LEGEND Communications System Release 6.1
Feature Reference 555-661-110
Features
Tandem Switching
Network Calls Routed via the Local System. This topic explains the
factors that you must consider when remote users, calling via ARS from a
networked system, use public switched telephone network facilities
connected to your own local system and/or have calls routed through your
system to another system where they are sent to the PSTN.
"Automatic Route Selection" on page 68
provide additional general information about these features.
Local Calls Routed to Other Systems
Local system users may use ARS to route calls over tandem trunks to the PSTN
facilities connected to a non-local system.
This arrangement can provide toll cost savings when users need to reach outside
numbers that are not in their own local calling area but are local to other systems
in a network. It also means that in some cases, a MERLIN LEGEND
Communications System may have only one or two PSTN trunks connected to it
for emergency purposes only. Under normal circumstances, the system uses
PSTN facilities connected to another system in the network, which can provide
call-volume advantages when buying PSTN services such as domestic long-
distance calling.
NOTE:
For intersystem calls among network extensions and for routing of DID and
PRI dial-plan routed calls that are sent across the network, UDP routing is
used. It is much like ARS routing, only simpler. Details are provided in
"Uniform Dial Plan Features" on page
To accommodate certain types of calls, enhance security, and make system
programming simpler, the systems in a network should all use the same ARS
access code. This code then cannot be included in the non-local dial plan of any
networked system, because system programming of the local ARS access code
into the non-local dial plan is blocked. If ARS access codes are not all the same,
great care must be taken not to program a non-local ARS access code into the
non-local dial plan. For example, if the ARS access code is 9, extension ranges
such as 9000–9050 should not be programmed. Programming the ARS access
code into the non-local dial plan can allow inadvertent access to ARS on a remote
system.
For detailed information on modifying ARS in order to allow calling out on PSTN
facilities connected to a non-local system in a network, refer to Network
Reference . The general rules are listed below:
Assign tandem trunks to a pool or pools including only one type of trunk
(PRI, T1-emulated tie programmed for voice and/or data, or analog tie). For
information about assigning trunks to pools, see
For 10xxx and 101xxxx equal access Interexchange Carrier (IXC), Dial 0,
and N11 calls from a collocated networked system that is not connected to
the PSTN, the tandem trunks must be assigned to the main pool so that
and "Remote Access" on page 578
710.
"Pools" on page
Issue 1
August 1998
Page 676
4 3
481.