ISDN:
Integrated Services
Digital Network.
ISDN
provides higher speeds than POTS by allowing data to be
transferred
digitally from end to end.
In
contrast POTS converts the digital data to analog within the local loop utilizing
a modem that extends into the home or office impacting transmission speed.
Converting to an ISDN compatible configuration for the
consumer requires additional pieces of hardware. Telecommuting to an office or base requires
additional equipment at the base. ISDN usage costs are
more expensive than analog telephone lines, users enjoy significant
benefits, which more than justify the costs.
ISDN
Phones and Equipment.
You'll need the following components for your
ISDN line installation:
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Network Termination (NT-1):
Provides the National ISDN-standard interfaces to the
telecommunications network.
(Phone Company)
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Terminal Adapter:
Allows you to use existing non-ISDN phones, FAX, & PC
communications interfaces.
(Customer Choice, examples 3COM
Impact IQ, Adtran EXPress3000,
etc.)
-
ISDN Telephone with Basic
Rate Interface (BRI): Fingertip access to ISDN functions.
Eliminates the need for a Terminal Adapter.
(Phone Company)
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Commercial AC Power:
Your ISDN telephone equipment will need access to a commercial power
source.
(Electric Company)
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Phone Company - Line
Lease Charges
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Bee.Net Connectivity -
Service to the Internet
Basic Rate Interface
There are two basic types of ISDN service: Basic Rate Interface
(BRI) and Primary Rate Interface (PRI). BRI
consists of two 64 kbps B channels and one 16 kbps D channel for a total
of 144 kbps. This basic service is intended to meet the needs of most
individual users.
Basic Rate Interface Basic
Rate, or BRI Service, consists of two full duplex 64 [Kbps] [B
Channels] and one 16 [D
Channel]. BRI lines are
typically deployed in small branch offices or in a home (telecommuting)
office, and can be referred to as 2B+D.
Channels
Voice and data are carried by bearer channels (B channels)
occupying a bandwidth of 64 Kbps (bits per second). Some switches limit
B channels to a capacity of 56 Kbps.
A data channel (D channel)
handles signaling at 16 Kbps or 64 Kbps, depending on the service type.
To access BRI service, it is necessary to subscribe
to an ISDN phone line. Customer must be within 18000 feet (about 3.4
miles or 5.5 km) of the telephone company central office for BRI
service; beyond that, expensive repeater devices are required, or ISDN
service may not be available at all.
Customers will also need special
equipment to communicate with the phone company switch and with other
ISDN devices. These devices include ISDN Terminal Adapters
(sometimes called, incorrectly, "ISDN Modems") and ISDN
Routers.
ISDN
Equipment and Interface Terminology
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U INTERFACE
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U-interface is a 2-wire digital telephone line that runs from the telephone company's central
office (CO) to an NT1 device. The customer is responsible for supplying
all the equipment from the U interface forward.
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NT-1
Network Termination Type
1
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The NT1 acts as the
boundary between the customer premise and the phone company's
network. NT1 is a Basic Rate ISDN-only device that converts a service provider's U-interface to a customer's S/T-interface. It can be stand-alone or integrated into a
terminal adapter.
The NT1 interface combines the 2 B Channels and the D
channel into a single bit stream at the physical level and is
also capable of supporting more than one device attached to an
ISDN line, sometimes referred to as a multi-drop configuration.
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S/T
INTERFACE
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S/T-interface is a common way of referring to either an S- or T-interface.
The S/T interface breaks
the signal into two paths- one transmit, one receive. In an ISDN PBX, the NT1
connects using the T interface, and the PBX connects using the S
interface. This intermediate track is called NT2.
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TE1
Terminal Equipment Type
1
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TE1 (Terminal Equipment Type 1) is ISDN-ready equipment that can directly connect to the ISDN line (often using an S/ T-interface). Examples are ISDN phones,
ISDN routers, ISDN computers, etc. They are manufactured from
the outset to be completely ISDN compatible.
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R
INTERFACE
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R-interface is a non-ISDN interface such as an EIA-232 or a V.35 interface.
A R-interface provides a non-ISDN interface between equipment
that is not ISDN compatible with the rest of the ISDN network.
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TA
Terminal
Adapter
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TA is a device that allows non-ISDN-ready equipment,
such as PCs, to connect to an ISDN line.
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TE2
Terminal Equipment Type
2
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TE2 is equipment that cannot directly connect to an ISDN line. A common example of this device is a PC, or a non-ISDN-ready router. A TA must be used to
connect to the ISDN line. Examples of TE2 are RS-232 or [X.25] interface
based devices, such as personal computers or 3270 terminals.
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SPID
Service
Profile ID
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The SPID is a
number assigned to an ISDN line by the ISDN service provider
that identifies certain characteristics of the line. Usually
this number is the telephone number PLUS 0101 as an
identifier.
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In the U.S., the telephone company
provides its BRI customers with a U interface. The U interface
is a two-wire (single pair) interface from the phone switch. It supports
full-duplex data transfer over a single pair of wires, therefore only a
single device can be connected to a U interface. This device is called a
Network Termination 1 (NT-1).
The NT-1 is a relatively simple device that converts the 2-wire U
interfaces into the 4-wire S/T interface. The S/T interface
supports multiple devices (up to 7 devices can be placed on the S/T bus)
because, while it is still a full-duplex interface, there is now a pair
of wires for receives data, and another for transmitting data. Today,
many devices have NT-1s built into their design.
Technically, ISDN devices must go through a Network Termination 2
(NT-2) device, which converts the T interface into the S interface
(Note: the S and T interfaces are electrically equivalent). Virtually
all ISDN devices include an NT-2 in their design. The NT-2 communicates
with terminal equipment, and handles the Layer 2 and 3 ISDN protocols.
Devices most commonly expect either a U interface connection (these have
a built-in NT-1), or an S/T interface connection.
Devices that connect to the S/T (or S) interface include ISDN capable
telephones and FAX machines, video teleconferencing equipment,
bridge/routers, and terminal adapters. All devices that are designed for
ISDN are designated Terminal Equipment 1 (TE1). All other
communication devices that are not ISDN capable, but have a POTS
telephone interface (also called the R interface), including
ordinary analog telephones, FAX machines, and modems, are designated Terminal
Equipment 2 (TE2). A Terminal Adapters (TA) connects a TE2 to
an ISDN S/T bus.
Going one step in the opposite direction takes us
inside the telephone switch. Remember that the U interface connects the
switch to the customer premises equipment. This local loop connection is
called Line Termination (LT function). The connection to other
switches within the phone network is called Exchange Termination
(ET function). The LT function and the ET function communicate via the V
interface.
EXAMPLES
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NETWORK INTERFACE
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RJ-45 for ISDN Basic Rate U-interface
(built-in NT1) 128 kbps
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DTE INTERFACE
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EIA-232 (DB-25)
Modem pass through port (3000 only)
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DTE DATA RATES
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1.2 to 230.4 kbps asynchronous
2400 to 128 kbps synchronous (3010 only)
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COMPRESSION
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hi/fn(R) LZSTM per PPP standard
Compatible with Ascend(R) compression
Compatible with Windows(R) 95/98 compression
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PROTOCOLS
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Multilink PPP, ITU-T V.120, Clear Channel,
Async BONDING,
Shiva PAP, AODI/BACP (3000 only)
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ISDN SWITCH COMPATIBILITY
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National ISDN-1, Lucent 5ESS(R), Nortel DMS-100TM
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DIALING SELECTIONS
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AT commands, DTR assertion, V.25 bis (3010 only)
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DIAGNOSTICS AND TESTING
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Network loopback
Remote configuration
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ANALOG PORTS
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Two standard RJ-11 (REN = 3)
Each port rings up to three phones
within 500 feet
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CUSTOM CALLING FEATURES
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Stutter dial tone
Three- and six-way conferencing
Call forwarding
Reminder ring
Auto call back
Distinctive ring
Caller ID
Implicit transfer
Visual message waiting indication
(Custom calling features must be
provided by telephone company.)
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ENVIRONMENT
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Operating Temperature: 0* to 50*C, (32* to 122*F)
Storage Temperature: -20* to 70*C, (-4* to 158*F)
Relative Humidity: Up to 95%, non-condensing
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PRODUCT INCLUDES
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110V wallmount power supply, CD ROM,
one cable to connect
ISDN line
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AGENCY APPROVALS
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Emissions: FCC Part 15 Class B
Safety: UL 1950, CUL
Telecom: FCC Part 68, Industry Canada CS-03
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