Eicon Technology Diva T/A User manual

DIVA T/A ISDN Modem
Reference Guide

Fourth Edition (July 1998) 206-193-04
DIVA T/A ISDN Modem is a trademark of Eicon Technology Corporation.
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Table of Contents
What is ISDN?......................................................................................4
ISDN stands for Integrated Services Digital Network..........................4
ISDN Communication Channels.........................................................6
Connecting to ISDN - BRI and PRI .................................................... 7
What is EZ-ISDN/IOC?.......................................................................8
What is AutoSPID? ............................................................................9
Non-Initializing Terminal Mode....................................................... 10
What is Multilink PPP?......................................................................11
What is BACP/BOD and DBA?.........................................................12
What is Always On / Dynamic ISDN (AO/DI)................................... 13
What is Data Compression?............................................................... 14
AT Commands....................................................................................15
Locating Commands......................................................................... 15
AT Command Format ...................................................................... 15
AT Command Groups ...................................................................... 16
Alphabetical List of Supported AT Commands................................. 17
AT Command Result Codes...............................................................73

DIVA T/A ISDN Modem Reference Guide 4
What is ISDN?
While you've heard of ISDN, there's a good chance you're unsure
whether you need it - or even what, exactly, it is. Even though ISDN
is globally available, it's so new that understanding it may require a
little investigation.
In simple terms, ISDN is a replacement for plain old telephone
service, which was never designed to meet the needs of the
information age. ISDN uses the same wiring that currently serves
homes and businesses. You get ISDN service from the same
companies who provide telephone service, and you use it to connect
telephones, computers, and fax machines. The difference is that you
get much faster, much more dependable connections for voice, data,
fax, and even video - all through a single line. There is no other
technology that comes close to delivering such communications
benefits today.
International ISDN standards were established about 10 years ago.
Since then, telephone companies throughout the world have raced to
upgrade their equipment to ISDN standards. As ISDN service
availability has spread, many millions of computer users have turned
to ISDN, and new users are coming on board even faster.
ISDN stands for Integrated Services
Digital Network
"Integrated Services" refers to ISDN's ability to deliver two
simultaneous connections, in any combination of data, voice, video,
and fax, over a single line. Multiple devices can be attached to the
line, and used as needed. That means an ISDN line can take care of
most people's complete communications needs, without forcing the
purchase of multiple analog phone lines at a much higher transmission
rate.
The "Digital" in ISDN refers to its purely digital transmission, as
opposed to the analog transmission of plain old telephone service. If
you're using a modem for Internet access at this moment, your
Internet service provider's modem has converted this site's digital
content to analog signals before sending it to you, and your modem
converts those signals back to digital when receiving (the same thing
happens with every keystroke and mouse click you transmit). When
you connect with ISDN, there is no analog conversion. ISDN
transmits data digitally, resulting in a very clear transmission quality.
There is none of the static and noise of analog transmissions that can
slow transmission speed.

DIVA T/A ISDN Modem Reference Guide 5
"Network" refers to the fact that ISDN is not simply a point-to-point
solution like a leased line. ISDN networks extend from the local
telephone exchange to the remote user and include all of the
telecommunications and switching equipment in between. When you
have ISDN, you can make connections throughout the world to other
ISDN equipment. If your ISDN equipment includes analog
capabilities, you can also connect to analog modems, fax machines,
and telephones, even though they may be connected to plain old
telephone service.
Benefits
While ISDN accommodates telephones and fax machines, its most
popular advantage is in computer applications. You can plug an ISDN
adapter into a phone jack, like you would an analog modem, and get a
much faster connection with no "line noise."
The most common ISDN service, Basic Rate Interface (BRI),
provides two 64 Kbps channels per line. When the two channels are
bonded in a single connection, you get a speed of 128 Kbps, which is
about four times the actual top speed of the fastest analog modems.
Compression can increase throughput to around 250 Kbps.
Telecommuters, for example, benefit immensely from ISDN. Whether
you access the corporate LAN in the evenings or maintain a full-time,
remote home office, ISDN is the next best thing to being there. E-
mail, database access, and file transfers improve dramatically, making
it seem like you're locally attached to the LAN.
Internet access is another great application for ISDN. Compared with
even the fastest modem access, ISDN makes Web graphics appear
almost immediately, and can reduce download times by over 75%.
ISDN can even provide advantages over shared, higher-bandwidth
office connections; PC Magazine advises that an ISDN connection
can deliver better performance than a T1 shared among users on a
LAN. And in many markets, it's actually cheaper than an isolated
analog business line.
Such large-scale file transfer applications as medical imaging,
insurance and law enforcement imaging, and the preparation of
printed materials are additional arenas where ISDN proves highly
beneficial. With the dramatic reduction in file transfer time, ISDN
makes even multi-megabyte files available to recipients within
minutes, not hours.
Videoconferencing is an emerging ISDN application that's growing
fast in popularity and ISDN is currently the only practical way of
making it happen.

DIVA T/A ISDN Modem Reference Guide 6
ISDN Communication Channels
In the ISDN interface, a number of communication channels are
carried over a digital line. These communication channels can vary by
the type of information they transmit and by the transmission speed
they support. The number and type of channels used may vary.
The communication channels can be of the following types:
B-Channel - 64 Kbps
D-Channel - 16 or 64 Kbps
H-Channel - 384, 1536, or 1920 Kbps (not yet commercially
available)
Different combinations of these channels are used to support different
types of usage (e.g., basic, primary and broadband).
B-Channel
The B-channel is a user (bearer) channel that carries a subscriber’s
digital traffic (e.g. digitized video, voice, audio, or digital data, or
perhaps a mixture). The bandwidth of this channel is 64 Kbps. The
control signals used to set up the connection, however, are not sent
over the B-channel. The call establishment is done on the D-channel
using common-channel signaling. This concept will be discussed
shortly.
Two kinds of connections can be established over a B-channel:
•Circuit-Switched
•Packet-Switched
Circuit-switched connections are ideal for voice traffic for several
reasons. Voice data is “delay-sensitive”, meaning that it must not be
delayed, and that it must be received in the order in which it was
transmitted. There is a call set-up time that is characteristic of circuit-
switched connections. This time lag is quite acceptable when
measured against the length of a typical telephone call.
In a packet-switched data network or PSDN, data to be transmitted is
broken up into individual units called packets that are then routed
from sender to receiver. The sender/receiver can be any type of
terminal, printer, computer or other device that supports an interface
to the network.

DIVA T/A ISDN Modem Reference Guide 7
D-Channel
The primary function of the D-channel is to carry common-channel
signaling information to manage and control circuit-switched calls on
B-channels.
The D-channel can also be used for packet-switching or low-speed
telemetry when it is not involved in control signaling. Message
signaling takes priority over data packet-switching.
The D-channel functions at 16 Kbps for Basic Rate Interface or 64
Kbps for Primary Rate Interface. The speed is dependent on the end-
user’s interface.
H-Channel
The H-channel is used for high-speed user data traffic at bit rates
higher than 64Kbps. Examples of services which require these higher
rates are: fast facsimile, teleconferencing, and video. An H-channel
user can subdivide the channel using TDM to meet specific
requirements.
Connecting to ISDN - BRI and PRI
There are two types of access interfaces to the ISDN: Basic Rate
Access (also referred to as Basic Rate Interface (BRI)) and Primary
Rate Access (also referred to as Primary Rate Interface (PRI)).
Basic Rate Access
Basic Rate Interface or Access consists of two B-channels operating
at 64 Kbps and one D-channel operating at 16 Kbps. It is also
commonly referred to as 2B+D.
Primary Rate Access
The primary rate interface is designed for users with large capacity
requirements.
There is no single transmission rate defined for primary rate access. In
North America and Japan, for example, primary rate interface is based
upon the T1 rate (defined in detail shortly) of 1.544 Mbps. In Europe,
by comparison, the rate is 2.048 Mbps.

DIVA T/A ISDN Modem Reference Guide 8
What is EZ-ISDN/IOC?
(North America only)
We highly recommend that you use our toll free ISDN ordering
service to make sure you get the correct ISDN line the first time. The
service is free to our customers. Dial 1-888-800-DIVA.
EZ-ISDN / IOC simplifies the ordering of your ISDN line. It lets you
use simple codes to order pre-configured packages of ISDN features
and services.
The North American ISDN User's Forum (NIUF) and Local Exchange
Carriers (LEC) administer the assignment of codes. Bellcore
administers the National ISDN Ordering Code (IOC) process.
We recommend the use of the following ISDN Ordering codes:
•IOC "S" offers basic voice/data features without the advanced
calling features described below. If you select this option, make
sure to get Additional Call (ACO). ACO is required for Call
Bumping (also known as Dynamic Bandwidth Allocation--DBA)
and Call Waiting to work correctly. IOC "S1" includes ACO,
however it is not supported everywhere.
•EZ-ISDN 1 (or IOC: "U") adds voice/data to both B-channels.
The Advanced calling features such as Call Conference, Call
transfer, etc., are only available on one B-channel.
•EZ-ISDN 1A (or IOC: "V") adds VoiceMail to EZ-ISDN 1.
•EZ-ISDN 3 or 3A. For the latest information on ordering Always
On/Dynamic ISDN (AO/DI), please refer to www.isdnzone.com.
ACO is required for Call Bumping(DBA) and Call Waiting to work
correctly. Calling Features are additional functions (such as Call
Forwarding, 3-way Call) available on DIVA T/A models equipped
with analog device ports.
Note: If you want to use DIVA T/A’s Calling Features, ask your ISDN
service provider for the values of the Feature Keys. You need these
values to ensure the DIVA T/A has full access to the features.

DIVA T/A ISDN Modem Reference Guide 9
What is AutoSPID?
(North America only)
AutoSPID is a new National ISDN protocol feature which enables the
DIVA T/A to download a list of Service Profile Identifiers (SPIDs),
Directory Number and Call Type information from the ISDN line, and
to determine whether the SPIDs are currently initialized by other
devices.
Note: Check with your ISDN service provider to determine if they
support the AutoSPID feature.
This feature effectively eliminates the need for you to configure any
ISDN parameters.
AutoSPID works in the following manner:
•If there are no SPIDs configured, then AutoSPID attempts to
determine and then assign SPIDs and DNs to the location
designated to store the AutoSPID parameters.
•If AutoSPID fails to detect the SPIDs, try entering the DNs (in a
10 digit format) and the DIVA T/A will attempt to perform
generic SPID guessing.
•Unless the SPIDs and DNs are configured correctly, whether
through AutoSPID, SPID guessing, or configured manually,
ISDN will fail to initialize (the D-LED will flash).
The only way to use the DIVA T/A without entering SPIDs, is to
configure the ISDN numbers for Non-Initializing Terminal mode.

DIVA T/A ISDN Modem Reference Guide 10
Non-Initializing Terminal Mode
(North America only)
Non-Initializing Terminal (NIT) mode is a new National ISDN
protocol feature which enables the DIVA T/A to operate without
SPIDs. Your ISDN provider must support NIT mode to be able to use
it.
To configure the DIVA T/A for Non-Initializing Terminal mode,
deselect the SPID checkbox in the Windows Configuration Tool, or
specify Yes for the Non-Initializing parameter in the VT-100
Configuration Tool.
Note: Check with your ISDN service provider to determine if they
support Non-Initializing Terminal mode.

DIVA T/A ISDN Modem Reference Guide 11
What is Multilink PPP?
Multilink PPP combines two 64 Kbps ISDN channels to provide a
maximum transmission speed of 128 Kbps.
The DIVA T/A serves as an intermediary between its host workstation
and the remote device to which data is being transmitted. All the
protocol processing required for the negotiation of a Multilink PPP
connection is performed on the DIVA T/A itself. The PC forwards
asynchronous PPP packets to the DIVA T/A which, in turn, converts
the packets for synchronous transmission and negotiates the various
authentications required to establish the Multilink PPP connection
with the target system over ISDN lines. This allows for the more
efficient use of the ISDN line without requiring any changes to the
PPP stack currently loaded on your PC.
DIVA T/A supports COM port rates of up to 230.4 kbps. However,
some computer COM ports are limited to 115.2 kbps. If you want to
use your DIVA T/A at its maximum speed, install a “fast COM port”
card (UART 16650 based).

DIVA T/A ISDN Modem Reference Guide 12
What is BACP/BOD and DBA?
BACP/BOD
DIVA T/A supports the Bandwidth Allocation Control Protocol
(BACP) and Bandwidth on Demand (BOD). These two features
combine to allow the DIVA T/A to establish multilink sessions that
provide larger amounts of bandwidth than that offered over a single
dialup channel. Such multilink sessions are established according to
procedures defined in the Internet Engineering Task Force (IETF)
PPP Multilink specification (RFC 1717).
BACP/BOD works by informing the DIVA T/A which dial-in ports
are presently available for a multilink session. It allows the answering
location to reserve those ports for the calling party and provides the
calling party with the telephone numbers of those ports.
BACP/BOD also allows a user at the calling location to establish a
multilink session by knowing only one telephone number instead of
all the numbers to be dialed for the full session. With BACP/BOD, the
answering location provides the calling location with a list of the
remaining telephone numbers to be used for the connection, and the
additional channels are dialed by the calling equipment transparently
to the user. This effectively raises a 64 kbps connection into a 128
kbps connection.
BACP/BOD also decides whether the second B-channel is required or
not. When bandwidth demand goes up, the second B-channel can
automatically be established, and conversely, when bandwidth
demand goes down, the second B-channel can be dropped. The
primary advantage, therefore, is a reduction of dial up charges; the
second B-channel is only used (and hence paid for) when required.
DBA
DIVA T/A also supports Dynamic Bandwidth Allocation (DBA),
known also as Call Bumping. DBA automatically drops one B-
channel to allow an incoming or outgoing telephone, fax or modem
call. When the voice call is over, DBA automatically re-establishes
the multilink session by reconnecting the second B-channel, if the
throughput requires it.
It is recommended that you use DBA with BACP/BOD so that you
can have greater flexibility when using the DIVA T/A.
Note: If an analog device is used on the server side of the connection,
DBA will not restore a channel that has been bumped.

DIVA T/A ISDN Modem Reference Guide 13
What is Always On / Dynamic
ISDN (AO/DI)
AO/DI is only available if you have subscribed to it, your ISDN
service provider supports it, and you are using Multilink PPP.
AO/DI uses the ISDN D-channel X-25 packet service to maintain an
"always on" connection between you and your Service Provider. Low
bandwidth requirements can be met using this constant connection,
such as sending and receiving e-mail, credit card verification, etc.
If additional bandwidth is required, for example, to download a large
file, AO/DI, in conjunction with Bandwidth on Demand (BOD),
automatically adds B-channels of 64 Kbps each, for a total of 128
Kbps speed when both B-channels are in use. When the additional
bandwidth is no longer required, one or both B-channels are dropped,
leaving the D-channel connection in place.
AO/DI enhances ISDN use in a number of ways:
•AO/DI can quickly and automatically adjust to the voice and data
needs of end-users. For example, if both B-channels are bonded
in a data connection, and an incoming call is received, one of the
B-channels is automatically freed up for the telephone call. If a
fax call also comes in, the remaining B-channel may be allocated
to the fax call. The data connection continues on the D-channel
until a B-channel is available, if needed.
•As B-channels are invoked only when additional bandwidth is
needed, connection costs are significantly reduced.

DIVA T/A ISDN Modem Reference Guide 14
What is Data Compression?
To establish communications over a PPP link, each end of the
connection must first send packets to configure and test the data link.
After the link has been established, optional facilities may be
negotiated as needed. One such facility is data compression. A wide
variety of compression methods may be negotiated, although typically
only one method is used for both directions of the link.
Data compression is a process where the effective throughput is
increased by encoding data in such a way that fewer bits are required
to represent it. For example, a text file might be compressed by
representing common words with single characters; thus if the word
“the” is represented by the character “@”, it will be transmitted three
times faster. Popular compression algorithms typically reduce the size
of the data by 50%, effectively doubling the rate at which it is
transmitted.
The Compression Control Protocol (CCP) works with MLPPP and is
responsible for configuring, enabling, and disabling data compression
algorithms on both ends of the point-to-point link. PC Compression
negotiation takes precedence over the DIVA T/A negotiation for
performance considerations (for example, the PC compression may
reduce the number of bytes that go through the serial interface, the PC
has the quicker CPU, etc.). The DIVA T/A compression negotiation,
however, will assume control should no compression be detected or
the initial negotiation fail. No user configuration is required to enable
the DIVA T/A’s compression functionality.
Compression algorithms currently supported by the DIVA T/A
include Stacker LZS (Hi/fn), MPPC (Microsoft), and Ascend.

DIVA T/A ISDN Modem Reference Guide 15
AT Commands
This section contains a description of all AT Commands relevant to
DIVA T/A.
Locating Commands
To make it easier for you to locate a command, this guide has
organized commands in two ways.
AT Commands are grouped into several categories. Use the table in
the section AT Command Groups on page 16 to locate the relevant
category.
An alphabetical list of commands is also available. It is found in the
section Alphabetical List of Supported AT Commands on page 17.
AT Command Format
When issuing AT commands, you must abide by the following syntax
conventions:
•A command line consists of a prefix, body, and terminator. Each
command line must begin with “AT” (except A/).
•AT commands must be terminated by a carriage return (except A/).
•Commands entered in upper or lower case are accepted.
•The body is a string of commands restricted to printable ASCII
characters (032 - 126).
•Space (ASCII 032) and control characters other than CR (ASCII
013) and BS (ASCII 010) in the command string are ignored.
•A command line may be aborted by entering < Ctrl-x > (ASCII
024).
•The default terminator is the ASCII <CR> character. Characters
that precede the AT prefix are ignored. This is programmable
through S-Register 3.
•The DIVA T/A recognizes the backspace character for editing.
When echo is enabled, a backspace or delete is echoed as a
backspace character followed by a space character, and another
backspace. The code used for the backspace character is
programmable through register S5. Values equal to 0 or greater than
32, or the carriage return character value, cannot be used for the
backspace character.

DIVA T/A ISDN Modem Reference Guide 16
AT Command Format—Continued
•The AT sequence may be followed by any command. Exceptions
are: ATZ (reset), ATD (dial), ATA (answer), AT>H (help), and
AT@MENU which cannot be followed by other commands on the
same command line.
•Execution of commands ATD and ATA, either as a result of a
direct command or a re-execute command, will be aborted if
another character is entered before completion of the handshake.
•The maximum number of characters on any command line is 80
(including “A” and “T”).
•If a syntax error is found in a command, the remainder of the line
will be ignored and an ERROR code will be returned.
•Missing decimal parameters (n) are assumed as 0.
•Most commands entered with parameters out of range will not be
accepted and the ERROR response will be returned to the DTE.
•The next command will only be accepted by the DIVA T/A once
the previous command has been fully executed.
AT Command Groups
Group See page
General AT Commands 28
ISDN Configuration Commands 32
COM Port Configuration Commands 37
S Register Commands 41
Call Control Commands 43
V.120 Configuration Commands 47
V.110 Configuration Commands 50
Profile Commands 51
Multilink PPP Commands 53
Always On / Dynamic ISDN Commands 57
Utility Commands 62
Analog Device Commands 67
Monitor Commands 72

DIVA T/A ISDN Modem Reference Guide 17
Alphabetical List of Supported AT
Commands
The following table summarizes the AT Commands supported by the
DIVA T/A. Go to the specified page number for more information.
Note: Static parameters are preceded by an asterisk “ *”. Changes
made to static parameters do not take effect immediately (this
contrasts with “dynamic” parameters where the changes take effect
the moment they are made). To implement a change to a static
parameter, use the AT&Wn command; the changes will be
implemented when you restart your system.
AT Command Description Page
ATA Answer Calls 43
ATDn Dial a Number 46
ATEn Local Echo 37
ATIn View Product Information 28
ATO Return Online 28
ATQn Quiet Result Codes 37
ATSn Establishes S-Registers nas the
selected register
41
ATSn=v S-Register nto Value v 41
ATS0=n Rings to Auto-Answer 41
ATS1? View Ring Count 46

DIVA T/A ISDN Modem Reference Guide 18
Alphabetical List—Continued
AT Command Description Page
ATSn? Reports the value of S-Register n
41
ATVn Result Code Format
37
ATWn Connect Message Control
37
ATXn Extended Result Codes
38
ATZn Restarts the DIVA T/A
51
AT!C1=n *ISDN Switch Type
32
AT!C4=n *Enable/Disable Non-Initializing mode
(first B channel)
33
AT!C5=n *Enable/Disable Non-Initializing mode
(second B channel)
33
AT!C6=n *ISDN SPID Number for first B-channel
(applicable to North America only)
33
AT!C7=n *ISDN SPID Number for second
B-channel (applicable to North America
only)
34
AT!D1=n
Specify DTE Speed. 34
AT!D2=n
Specify Databits length 34
AT!D3=n
Specify Parity 34
AT!D4=n
Specify number of Stopbits. 34

DIVA T/A ISDN Modem Reference Guide 19
Alphabetical List—Continued
AT Command Description Page
AT!E0=n V.120 N201 Tx (Maximum Transmit
Frame Size)
47
AT!E1=n V.120 N201 Rx (Maximum Receive
Frame Size)
47
AT!E2=n V.120 Multiframe Mode
47
AT!E3=n V.120 K Window Size 48
AT!E4=n V.120 T200 (Retransmission Timer)
48
AT!E5=n V.120 N200 (Maximum Retry Count)
48
AT!E6=n V.120 T203 (Link Integrity Timer)
48
AT!E7=n
V.120 Idle Timer 49
AT!Ln *ISDN Encoding Law
34
AT!N1=n *ISDN Number for first B-channel
35
AT!N2=n *ISDN Number for second B-channel
35
AT!N3=n *ISDN Subaddress for first B-channel
35
AT!N4=n *ISDN Subaddress for second
B-channel
36
AT!On Default Outgoing Call Type
36
AT!T1=n Incoming ISDN Call on first B-channel
43

DIVA T/A ISDN Modem Reference Guide 20
Alphabetical List—Continued
AT Command Description Page
AT!T2=n Incoming ISDN Call on second B-
channel
43
AT!V0=n V.110 Configuration Override
50
AT!V1=n V.110 Stream Rate
50
AT!V2=n V.110 Character Length
50
AT!V3=n V.110 Parity
50
AT!V4=n V.110 Stop Bits
50
AT!V5=n V.110 Flow Control
50
AT!X1=n Specifies the X.25 version you are using. 57
AT!X2=n Specifies the X.25 DTE address. 57
AT!X3=n Specifies the X.25 facilities that are to be
included each time a call is made. 57
AT!X4=n Specifies the local ISDN prefixes to be
used. 58
AT!X5=n Specifies the X.25 default window size. 58
AT!X6=n Specifies the X.25 maximum window
size 58
AT!X7=n Specifies the X.25 default packet size 58
AT!X8=n Specifies the X.25 maximum packet size 59