Rockwell SoniCrafter BT8960 - Manual (Page 16)

6
1.0 System Overview
1.2 Applications
Bt8960
Single-Chip 2B1Q Transceiver
N8960DSB
1.2.2 Internet Connectivity Transport
The growth of the Internet has created a tremendous demand for additional band-
width in the local loop. When existing loop facilities are used to provide connec-
tivity to Internet servers, they are limited to the 128 kbps offered by Basic Rate
ISDN (BRI) service. Although those same loops could be provisioned through
HDSL (for E1 or T1 transport rates), the tariff structure for these services puts
their bandwidth beyond the practical reach of most consumers. It is unlikely that
the E1/T1 tariff structure will change soon since it still represents significant
value for business customers using E1/T1 leased lines for corporate data and
voice exchange.
The 128 kbps rate offered by BRI is sufficient for the text and graphic content
of most of today's home pages. However, when motion, video, or interactivity are
added, the data rate required is increased to well over 300 kbps.
The advent of the Bt8960 creates an intermediate solution between BRI and
E1/T1 which opens a host of low-cost, higher bandwidth possibilities. With the
Bt8960, local loops could be provisioned for data rates up to 384 kbps with low-
cost hardware. In addition, the full ISDN 18,000 ft. carrier service area could be
served with a higher data rate. Enabling hardware could, for example, take the
form of LAN extender equipment, and terminals for such equipment could have
standard Ethernet connections to routers, personal computers, or workstations.
The terminals could also use the Bt8960 2B1Q transport mechanism for the local
loop link to the central office or Internet server location.
By placing a SLIC in the terminal and reserving a 64 kbps channel for voice
transport, simultaneous data and voice service could be offered over a single
twisted pair. The extraordinary low power of the Bt8960 allows for customer site
equipment to be remotely powered, thereby guaranteeing lifeline POTS service in
the event of power loss at the customer site.
Figure 1-3. PCM6 Voice Pairgain Block Diagram
SLIC
SLIC
SLIC
SLIC
SLIC
SLIC
PCM
Framer Bt8960
Local
Loop