Software of the Month Club 1996 January/SOFM_Jan1996.bin/pc/os2/zoc/install.fil/DEVISDN.HLP

OS/2 Help File | 1995-11-27 | 9KB | 191 lines

ΓòÉΓòÉΓòÉ 1. Informations about the ISDN device ΓòÉΓòÉΓòÉ

The ISDN device lets ZOC access CAPI V1.1 DLLs which are supplied with most
ISDN boards.

Topics:

o Using the ISDN device
o ISDN protocol options
o ISDN global options
o ISDN primer
o Tested ISDN boards


ΓòÉΓòÉΓòÉ 1.1. Using the ISDN device ΓòÉΓòÉΓòÉ

 The ISDN device can be selected in Options->Serial, if you installed your ISDN
board's CAPI.DLL in a directory that is listed in the LIBPATH statement in your
CONFIG.SYS.

The options window will come up, if you press the Device-Options button.  In
the phone book, it is possible to select a device for each phone book entry
(from the Device listbox).  With the Setup button in the phone book you will
set the device options only for this phone book entry.  This way it is possible
to have different phone book entries use the same device with different
options.  In REXX you can activate the ISDN device with 'SETDEVICE "ISDN"'.


ΓòÉΓòÉΓòÉ 1.2. ISDN protocol options ΓòÉΓòÉΓòÉ

 The ISDN device has a wealth of options (most of which you'll probably never
need).  To relieve you of the burden of dealing with the subtleties of these
settings, the options dialog offers nine buttons to set the most commonly used
combinations of settings.  However, if you are interested, you can find
informations to all settings in ISDN primer

 B2 Protocol
    Here you can select between ten layer-2 proctocols.  However, not all
    manufacturers implement all protocols.  Only X.75 is required; hence it is
    the default.

 B2 Frame Size
    The frame size (block size) can be set from 128 to 2050 bytes.  Frame sizes
    greater 2048 bytes (plus overhead) are not allowed in CAPI V1.1 and should
    not be used.

 B2 Window
    The B2 window can be selected between two and seven and sets the number of
    ISDN messages that can be sent from the remote host without acknowledgement
    from ZOC.

 B3 Protocol
    ISDN supports five protocols in layer-3.  CAPI V1.1 defines T70NL as the
    standard protocol, but CFOS (for DOS and OS/2) and ISDNCOM/2 seem to have
    established TRANSPARENT as the most commonly used protocol in the PC world
    (at least in Germany).  This protocol disables layer-3 (saving a bit of
    control overhead).

 Service Primary
    The primary service indicator is sent to the remote site when a connection
    is requested (ie. when you make a call) asking for the corresponding
    service. 64kbit/sec data is coded as 7, german videotex
    (BTX/Datex-J/T-Online) is 5.

 Service Additional
    The additional service indicator transfers optional parameters for the
    requested primary service.

 Predefined
    These buttons set the above parameters to predefined configurations.
    'Standard options' will work in most cases (especially if you call hosts
    which use CFOS or ISDNCOM).

 Global
    This button opens the ISDN global options window, where you can set general
    options for your ISDN board.


ΓòÉΓòÉΓòÉ 1.3. ISDN global options ΓòÉΓòÉΓòÉ

 This window is opened with the Global-Options button.  The parameters set here
are used in all ISDN sessions (and not just in the entry from where you opened
this window).

 Incoming EAZ mask
    Here you can select EAZs for which ZOC will accept incoming calls.  EAZ is
    a concept of national German ISDN (upon which CAPI V1.1 is based). If you
    are using DSS1 (or so called Euro-ISDN), you will have a utility to map
    incoming phone numbers to the one digit EAZs.

 Source EAZ
    Here you supply the EAZ which the ISDN device will use for outgoing calls.
    In DSS1 this controls the caller ID that is transmitted to the called host.

 Controller ID
    If you are using more than one ISDN board simultaneously, select the board
    ID here (default is 0).

 Set system time to ISDN time
    Since ISDN transfers the exact system time when a call is made, you can
    select, to set your computer's time accordingly.


ΓòÉΓòÉΓòÉ 1.4. ISDN primer ΓòÉΓòÉΓòÉ

 Here is an little ISDN dictionary:

 ISDN
    ISDN means Integrated Serviced Digital Network.  It offers digital transfer
    of different services (like phone, fax, video conferencing, etc.) over one
    line.  All data is transferred with 64000 bits per second per B-channel (of
    which there are two in German Telekom's standard DSS1/Euro-ISDN offer).
    There is another channel, the so called D-channel, which carries control
    information to maintain the B-channels.  The use of the D-channel differs
    between national ISDN implementations.

 DSS1 and MSN, 1TR6 and EAZ
    DSS1 (Euro-ISDN) is a European standard which is about to replace the
    national standards.  Incoming calls are routed to the telephony devices
    (phone, fax, etc.) according to the MSN (Multipel Subscriber Numbers).  One
    S0 socket has several "phone numbers".  Each number can map to several
    devices if the devices service different service-indicators.

    1TR6 is the German national ISDN protocol which will be offered from
    Telekom only until the year 2000.  1TR6 selects the devices according to
    EAZs (EndgerДte Auswahl Ziffern (Device Selection Digits)).  A 1TR6 socket
    has only one "phone number" to which the EAZ is appended to make a full
    phone number calling a certain device connected to an 1TR6 socket. EAZ 2 is
    generally used for 64kbit communication.

 CAPI
    CAPI means 'Common ISDN Application Programming Interface' and offers a
    defined interface between ISDN board and software application.  It is the
    meeting point of application developers and board manufacturers.  If both
    adhere to the standard, theoretically every application would work with
    ever ISDN board. Currently there are two CAPI definitions; CAPI V1.1 is
    based on the German 1TR6 standard (and able to deal with DSS1 only after
    mapping MSNs to EAZs), while it's successor CAPI 2.0 isn't generally
    offered with ISDN boards.

 B2/B3 protocol
    Data is transferred through the ISDN network in several layers and with
    several protocols.  There are ten protocols in layer 2 and five in layer 3
    (on of these, TRANSPARENT, disables layer 3).

 B2/B3 frame size
    Within the layers data is sent in packets.  These packets must not be
    larger than a certain maximum size, which is called the frame size.

 B2/B3 window size
    A window size sets the number of messages that can be sent, before the
    first one must be acknowledged, or, in other words, the maximum amount of
    unacknowledged messages at any time. The B3 window size controls, how many
    packets ZOC may send to CAPI, while the B2 window size controls the data
    flow between the local and the remote ISDN board.  A B2 window of 1 would
    slow noticeably down communication; values greater 2 hardly improve
    transfer speed at all (not all remote hosts can take a window size larger
    than two).

 Service Indicator
    Service indicators are transmitted together with a connection request when
    making a call.  The callee can determine if the called number can offer the
    requested service and refuse or accept the call (or map the call to one of
    several devices hooked to the same number).

 V110
    V110 is an alternate B2 protocol to emulate asynchronous connections over
    ISDN (eg. with ELSA's elink modems).

 Channel Bundling
    Some manufacturers offer an option to logically bundle two B channels. Two
    channels, like a two lane street, can carry more traffic and will almost
    double the transfer speed (an additional control overhead is required
    though).  However, such connections are only possible, if the remote host
    offers them as well (and is using the same manufacturer's board).  And, of
    course, it does cost double.


ΓòÉΓòÉΓòÉ 1.5. Tested ISDN boards ΓòÉΓòÉΓòÉ

 ISDN boards of the following manufacturers are tested with this ZOC.

o AVM
o BINTEC
o CREATIX (only CAPI 2.72 and 2.97)
o ELSA
o DIEHL
o IBM
o TELES (only CAPI 2.72 and 2.97)