Continued....
So the question than becomes
this.
Which is better in the sense of
connection speed and for Video conferencing between ISDN PRI
(1.544Mbps) to ADSL (1.544Mbps)?
PRI ISDN T1 is the industrial
strength flavor of ISDN, and is intended for users with much
greater capacity requirements. PRI has 23 B channels plus one 64
Kbps D channel. Each channel has a 64Kbps capacity, enabling a
total transmission speed of up to 1.536Mbps. With PRI ISDN, you
can pre-define the number of channels used for specific types of
calls or data delivery. What this means is that you can use the
various channels for accomplishing different things on different
channels simultaneously. In other words, PRI ISDN offers much
greater flexibility than that provided by BRI ISDN.
Additionally, the D channel is used as the switching channel
that communicates with the Central Office for Call Management.
It is used to carry local and long distance traffic.
An ADSL circuit connects an ADSL
modem on each end of a twisted-pair telephone line, creating
three information channels -- a high speed downstream channel, a
medium speed duplex channel, depending on the implementation of
the ADSL architecture, and a POTS (Plain Old Telephone Service)
or an ISDN channel. The POTS/ISDN channel is split off from the
digital modem by filters, thus guaranteeing uninterrupted
POTS/ISDN, even if ADSL fails. The high speed channel ranges
from 1.5 to 6.1 Mbps, while duplex rates range from 16 to 832
kbps. Each channel can be submultiplexed to form multiple, lower
rate channels, depending on the system.
ADSL modems provide data rates
consistent with North American and European digital hierarchies
and can be purchased with various speed ranges and capabilities.
The minimum configuration provides 1.5 or 2.0 Mbps downstream
and a 16 kbps duplex channel; others provide rates of 6.1 Mbps
and 64 kbps duplex. Products with downstream rates up to 8 Mbps
and duplex rates up to 640 kbps are available today. ADSL modems
will accommodate ATM transport with variable rates and
compensation for ATM overhead, as well as IP protocols.
When
deciding on the best bandwidth configuration to run
your video conferencing on...you may think you have
endless choices. Sometimes it appears that way when
you may actually be limited to just a few. Here's a
comparison when your only choices are between ISDN and
ADSL.
