Toshiba Strata DK14 General Description Manual page 88

Features
System Features
BRI applications for the DK424 will include video conferencing, remote access servers, faster
Internet access, point-of-sale devices and high-speed data connections from ISDN stations to the
public ISDN network, as well as typical voice and fax connections. With the correct external
adapter, data can be sent up to 128 kbps.
Like PRI, BRI provides CNIS, DID, Direct Inward Lines, and other data access services when
used to access the public network.
The Strata DK424 BRI cards will support both station side and trunk side connections. The Strata
DK424 system will also support BRI interface from the public network as a CO line service. There
are two types of ISDN BRI interfaces: S/T type (via RBSU/RBSS) and the U-type (via RBUU/
RBUS). Both types are used in the U.S.
The Public Switched Telephone Network provides BRI U-type lines only; therefore, a dealer-
supplied, external Network Terminal Unit (NT-1) is required to connect DK S/T-type BRI line
circuits to the network. The NT-1 must be UL listed (U.S.) or CSA certified (Canada).
Call-by-Call Service Selection
This feature permits the grouping of individual PRI B-channels to be shared among various types
of services specified by the customer, instead of having to dedicate each channel to a particular
type of service. Using this common pool of channels provides much improved traffic handling
than using dedicated channels.
This dynamic allocation of service can reduce the number of circuits required to access various
services, especially if various services have different peak busy periods.
In Release 4.15, the DK424 will enable specifying the minimum and maximum number of B-
channels used for each service on a common set of B-channels in system programming. Minimum
and maximum values can be set for three time periods during the day.
These values can be used to ensure that a minimum number of channels remain available for
incoming calls. They can also be used to determine if calls should be rejected because they exceed
the maximum number subscribed for that service. Until Release 4.15 becomes available, Call-by-
Call minimum/maximum service will be implemented at the CO.
Call-by-Call services can be specified to map Strata DK capabilities to network services such as
DID, Tie, FX, WATS, 800, etc. These services can be provided via the local telephone carrier or be
connected to any ISDN inter-exchange carrier.
Outgoing calls, specific numbers, or DID numbers can be checked against the Call-by-Call table
which lists all valid DNs. DNs can be identified on a per station basis to enable billing calls to a
selected service or station. All numbers used for identifying the call must be subscribed from the
providing service, otherwise the call will be rejected by the provider.
Non-Facility Associated Signaling (NFAS)
NFAS provides the ability to create ISDN trunk groups beyond the 23 channels available with a
single PRI. This is extremely important when Call-by-Call Services are used since all B-channels
must be controlled using a common D-channel.
The Strata DK system will support one additional PRI (two circuits to be linked with one D-
channel). This extends the number of call-by-call B-channels to 47 (2 x 24 minus 1). This provides
better performance and cost savings in high volume ISDN PRI applications.
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