Instruction manual

OVERVIEW
● Tie Trunks for linking PBXs with dedicated private circuits for high volume calling.
Dial access to stations, other trunks, answering groups (Direct Group Calling), and an
Electronic Tandem Network endpoint capability are provided.
● Off-Premises Stations (OPS) allow single-line voice terminals and key systems to be
located remotely and connected to System 25 via arrangements with the local
telephone company.
This service is used to provide users at secondary sites (or
their residences) many of the same features as an on-premises single-line station.
To enhance the usage and control of the above set of network facilities, System 25 provides
the rich set of access features outlined in the Outgoing Business Communications section.
In addition, System 25 can support networking between systems by:
● Serving as an endpoint on an electronic tandem network (ETN) using its tie trunks
and flexible dialing plan.
● Serving as an off-network or on-network access point with its dial access/transfer
between tie trunks and telephone company trunks (LS/GS/DID). This allows usage of
tie trunks to reach a distant System 25 and then connect through that System 25 to
local telephone company facilities to complete the call.
To support efficient utilization of trunks, they can be grouped together (up to 16 groups) if all
trunks in the group perform the same function.
This resource pooling provides better service
with a given number of trunks, and simplifies administration and calling.
Types of trunks that can be assigned in System 25 are as follows.
● Central Office, which provide a link with the local telephone company for incoming
and outgoing calls (LS/GS)
● Foreign Exchange (FX), which connect to a CO other than the local CO for high
volume calling to/from a distant location
● Wide-Area Telecommunications Service (WATS), which connect to an Outward WATS
office or a dial “800” Service Office
● Direct Inward Dialing (DID), which provide incoming service from a CO to directly
access a station or facility (STARLAN NETWORK interface, trunk group)
● Tie, which provide a link with another private switching system.
To support efficient utilization of this rich set of network options, System 25 provides the
functions outlined in the Incoming and Outgoing Business Communications sections.
Conclusions
System 25 has been targeted at providing excellent small business communications
capability at the right price.
The thousands of systems in service in the first 2 years of
production have confirmed that these capabilities are an excellent match with small business
customers’ communications needs.
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