Back
To Top
Q.
Won't DSL hurt the market for ISDN?
A. The answer to that question
is yes and no. DSL is most prevelant in heavily populated areas
such as cities and their surrounding suburbs. Since DSL is limited
to about 36,000 feet from your local telephone company's central
office, people in the countryside are limited in their choices
for Internet Access. That's where ISDN comes in. ISDN lines can
be run virtually anywhere as the lines themselves have signal
repeaters every so many thousand feet to keep your connection
to the Internet fresh and strong. ISDN is often the only high-speed
alternative to 56k modem access for people who live away from
the cities.
Back
To Top
Q.
What do I need in order to have ISDN access?
A. You need an ISDN router
or an ISDN "modem," which really isn't a modem,
rather it is the most commonly used term for the ISDN device that
dual-channel customers use. It is meant to connect only one computer
at a time to the Internet. An ISDN router is used to create Local
Area Networks (LAN) for businesses who want more than one computer
hooked up to the same Internet connection.
Routers
will be external devices and will be connected to the computers
by way of an ethernet, cable, ethernet card or a serial port.
ISDN modems will most likely be external devices linked to a computer
with an ethernet card or serial port, though internal ISDN modems
are manufactured.
Lastly,
you will also need ISDN lines run from you local telephone
company to your house or business. They will have a monthly charge
to be determined by the your local phone company.
Back
To Top
Q.
What does ISDN access consist of?
A. ISDN access consists of
Data Channels (B-channels) and a Signaling Channel (D-channel).
Dual channel access comes with two 64kbps channels and one 16kbps
signaling channel, sometimes called the Basic Rate Interface
(BRI).
B-channel:
"Bearer"-channel can be configured by the local phone
company to carry voice and/or data (one analog phone call or one
64kbps Internet connection).
D-channel:
"Delta"-channel carries control and signaling data (16kbps).
Back
To Top
Q.
How can a I have both voice and data over one connection?
A. If you have at least two
ISDN lines, one or both may be configured by the local phone company
to carry voice and/or data. For example, a dual-channel user has
one line configured for voice. When a phone call comes down the
line, one of the ISDN channels will stop transmitting data from
the internet and carry the phone call instead. Therefore the internet
connection will drop from 128kbps to 64kbps as one of the data
channels will be used for the phone call and one will be used
for the Internet connection.
Back
To Top
Q.
How far can ISDN lines be run?
A. ISDN lines can be run just
about anywhere. The ISDN lines have signal repeaters every so
many thousand feet, doing that keeps the digital signal strong
and clear and thus the connection is much more stable and faster
than 56k modem access.
Back
To Top
Q.
What are the SPID numbers?
A. The SPID numbers are the
telephone numbers that uniquely identify the B-channel ISDN lines
on the network. Just like analog phone lines have a telephone
number, so do ISDN lines. If an ISDN line was configured for data
and voice, the SPID number would be the phone number that someone
would call to ring a phone connected to the ISDN line. Let's take
an example: a ficticious ISDN line has the SPID number XXX-XXXX
and is configured for both data and voice. If someone were to
call the telephone connected to the ISDN line, the person would
need to dial XXX-XXXX.
Back
To Top