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README for the ISDN-subsystem

1. Preface

  1.1 Introduction

  This README describes how to set up and how to use the different parts

  of the ISDN-subsystem.

  For using the ISDN-subsystem, some additional userlevel programs are

  necessary. Those programs and some contributed utilities are available

  at

   ftp.franken.de

   /pub/isdn4linux/isdn4k-utils-.tar.gz

  We also have set up a mailing-list:

   The isdn4linux-project originates in Germany, and therefore by historical

   reasons, the mailing-list's primary language is german. However mails

   written in english have been welcome all the time.

   to subscribe: write a email to majordomo@hub-wue.franken.de,

   Subject irrelevant, in the message body:

   subscribe isdn4linux 

   To write to the mailing-list, write to isdn4linux@hub-wue.franken.de

   This mailinglist is bidirectionally gated to the newsgroup

     de.alt.comm.isdn4linux

  There is also a well maintained FAQ (both english and german) available

  at ftp.franken.de in /pub/isdn4linux/FAQ/

  This FAQ is also available at http://www.lrz-muenchen.de/~ui161ab/www/isdn/

  1.1 Technical details

  In the following Text, the terms MSN and EAZ are used.

  MSN is the abbreviation for (M)ultiple(S)ubscriber(N)umber, and applies

  to Euro(EDSS1)-type lines. Usually it is simply the phone number.

  EAZ is the abbreviation of (E)ndgeraete(A)uswahl(Z)iffer and

  applies to German 1TR6-type lines. This is a one-digit string,

  simply appended to the base phone number

  The internal handling is nearly identical, so replace the appropriate

  term to that one, which applies to your local ISDN-environment.

  When the link-level-module isdn.o is loaded, it supports up to 16

  low-level-modules with up to 64 channels. (The number 64 is arbitrarily

  chosen and can be configured at compile-time --ISDN_MAX in isdn.h).

  A low-level-driver can register itself through an interface (which is

  defined in isdnif.h) and gets assigned a slot.

  The following char-devices are made available for each channel:

  A raw-control-device with the following functions:

     write: raw D-channel-messages (format: depends on driver).

     read:  raw D-channel-messages (format: depends on driver).

     ioctl: depends on driver, i.e. for the ICN-driver, the base-address of

            the ports and the shared memory on the card can be set and read

            also the boot-code and the protocol software can be loaded into

            the card.

   O N L Y !!!  for debugging (no locking against other devices):

   One raw-data-device with the following functions:

     write: data to B-channel.

     read:  data from B-channel.

   In addition the following devices are made available:

   128 tty-devices (64 cuix and 64 ttyIx) with integrated modem-emulator:

   The functionality is almost the same as that of a serial device

   (the line-discs are handled by the kernel), which lets you run

   SLIP, CSLIP and asynchronous PPP through the devices. We have tested

   Seyon, minicom, CSLIP (uri-dip) PPP and mgetty (compiled with NO_FAX),

   XCept.

   The modem-emulation supports the following:

           1.3.1 Commands:

               ATA      Answer incoming call.

               ATD Dial, the number may contain:

                        [0-9] and [,#.*WPT-S]

                        the latter are ignored until 'S'.

                        The 'S' must precede the number, if

                        the line is a SPV (German 1TR6).

               ATE0     Echo off.

               ATE1     Echo on (default).

               ATH      Hang-up.

               ATH1     Off hook (ignored).

               ATH0     Hang-up.

               ATI      Return "ISDN for Linux...".

               ATI0        "

               ATI1        "

               ATI2     Report of last connection.

               ATO      On line (data mode).

               ATQ0     Enable result codes (default).

               ATQ1     Disable result codes (default).

               ATSx=y   Set register x to y.

               ATSx?    Show contents of register x.

               ATV0     Numeric responses.

               ATV1     English responses (default).

               ATZ      Load registers and EAZ/MSN from Profile.

               AT&Bx    Set Send-Packet-size to x (max. 4000)

                        The real packet-size may be limited by the

                        low-level-driver used. e.g. the HiSax-Module-

                        limit is 2000. You will get NO Error-Message,

                        if you set it to higher values, because at the

                        time of giving this command the corresponding

                        driver may not be selected (see "Automatic

                        Assignment") however the size of outgoing packets

                        will be limited correctly.

               AT&D0    Ignore DTR

               AT&D2    DTR-low-edge: Hang up and return to

                        command mode (default).

               AT&D3    Same as AT&D2 but also resets all registers.

               AT&Ex    Set the EAZ/MSN for this channel to x.

               AT&F     Reset all registers and profile to "factory-defaults"

               AT&Sx    Set window-size (x = 1..8) (not yet implemented)

               AT&V     Show all settings.

               AT&W0    Write registers and EAZ/MSN to profile. See also

                        iprofd (5.c in this README).

               AT&X0    BTX-mode off (default)

               AT&X1    BTX-mode on. (S13.1=1, S14=0, S16=7, S18=7, S19=0)

           For voice-mode commands refer to README.audio

           1.3.2 Escape sequence:

               During a connection, the emulation reacts just like

               a normal modem to the escape sequence +++.

               (The escape character - default '+' - can be set in the

               register 2).

               The DELAY must at least be 1.5 seconds long and delay

               between the escape characters must not exceed 0.5 seconds.

           1.3.3 Registers:

              Nr.  Default  Description

                            (no auto-answer if S0=0).

              1    0        Count of rings.

              2    43       Escape character.

                            (a value >= 128 disables the escape sequence).

              3    13       Carriage return character (ASCII).

              4    10       Line feed character (ASCII).

              5    8        Backspace character (ASCII).

              6    3        Delay in seconds before dialing.

              7    60       Wait for carrier (ignored).

              8    2        Pause time for comma (ignored)

              9    6        Carrier detect time (ignored)

             10    7        Carrier loss to disconnect time (ignored).

             11    70       Touch tone timing (ignored).

             12    69       Bit coded register:

                            Bit 0:    0 = Suppress response messages.

                                      1 = Show response messages.

                            Bit 1:    0 = English response messages.

                                      1 = Numeric response messages.

                            Bit 2:    0 = Echo off.

                                      1 = Echo on.

                            Bit 3     0 = DCD always on.

                                      1 = DCD follows carrier.

                            Bit 4     0 = CTS follows RTS

                                      1 = Ignore RTS, CTS always on.

                            Bit 5     0 = return to command mode on DTR low.

                                      1 = Same as 0 but also resets all

                                          registers.

                                      See also register 13, bit 2

                            Bit 6     0 = DSR always on.

                                      1 = DSR only on if channel is available.

                            Bit 7     0 = Cisco-PPP-flag-hack off (default).

                                      1 = Cisco-PPP-flag-hack on.

             13   0         Bit coded register:

                            Bit 0:    0 = Use delayed tty-send-algorithm

                                      1 = Direct tty-send.

                            Bit 1:    0 = T.70 protocol (Only for BTX!) off

                                      1 = T.70 protocol (Only for BTX!) on

                            Bit 2:    0 = Don't hangup on DTR low.

                                      1 = Hangup on DTR low.

                            Bit 3:    0 = Standard response messages

                                      1 = Extended response messages

                            Bit 4:    0 = CALLER NUMBER before every RING.

                                      1 = CALLER NUMBER after first RING.

             14   0         Layer-2 protocol:

                                      1 = X75/LAPB with UI-frames

                                      2 = X75/LAPB with BUI-frames

                                      3 = HDLC

                                      4 = Transparent (audio)

             15   0         Layer-3 protocol: (at the moment always 0)

             16   250       Send-Packet-size/16

             17   8         Window-size (not yet implemented)

             18   4         Bit coded register, Service-Octet-1 to accept,

                            or to be used on dialout:

                            Bit 0:    Service 1 (audio) when set.

                            Bit 1:    Service 5 (BTX) when set.

                            Bit 2:    Service 7 (data) when set.

                            Note: It is possible to set more than one

                                  bit. In this case, on incoming calls

                                  the selected services are accepted,

                                  and if the service is "audio", the

                                  Layer-2-protocol is automatically

                                  changed to 4 regardless of the setting

                                  of register 14. On outgoing calls,

                                  the most significant 1-bit is chosen to

                                  select the outgoing service octet.

             19   0         Service-Octet-2

             20   0         Bit coded register (readonly)

                            Service-Octet-1 of last call.

                            Bit mapping is the same as register 18

             21   0         Bit coded register (readonly)

                            Set on incoming call (during RING) to

                            octet 3 of calling party number IE (Numbering plan)

                            See section 4.5.10 of ITU Q.931

             22   0         Bit coded register (readonly)

                            Set on incoming call (during RING) to

                            octet 3a of calling party number IE (Screening info)

                            See section 4.5.10 of ITU Q.931

  Last but not least a (at the moment fairly primitive) device to request

  the line-status (/dev/isdninfo) is made available.

  Automatic assignment of devices to lines:

  All inactive physical lines are listening to all EAZs for incoming

  calls and are NOT assigned to a specific tty or network interface.

  When an incoming call is detected, the driver looks first for a network

  interface and then for an opened tty which:

  1. is configured for the same EAZ.

  2. has the same protocol settings for the B-channel.

  3. (only for network interfaces if the security flag is set)

     contains the caller number in its access list.

  4. Either the channel is not bound exclusively to another Net-interface, or

     it is bound AND the other checks apply to exactly this interface.

     (For usage of the bind-features, refer to the isdnctrl-man-page)

  Only when a matching interface or tty is found is the call accepted

  and the "connection" between the low-level-layer and the link-level-layer

  is established and kept until the end of the connection.

  In all other cases no connection is established. Isdn4linux can be

  configured to either do NOTHING in this case (which is useful, if

  other, external devices with the same EAZ/MSN are connected to the bus)

  or to reject the call actively. (isdnctrl busreject ...)

  For an outgoing call, the inactive physical lines are searched.

  The call is placed on the first physical line, which supports the

  requested protocols for the B-channel. If a net-interface, however

  is pre-bound to a channel, this channel is used directly.

  This makes it possible to configure several network interfaces and ttys

  for one EAZ, if the network interfaces are set to secure operation.

  If an incoming call matches one network interface, it gets connected to it.

  If another incoming call for the same EAZ arrives, which does not match

  a network interface, the first tty gets a "RING" and so on.

  As soon as voice gets supported (with the availability of the Diehl-driver),

  the service-identifier will be evaluated in addition.

2 System prerequisites:

  ATTENTION!

  Always use the latest module utilities. The current version is

  named in Documentation/Changes. Some old versions of insmod

  are not capable of setting the driver-Ids correctly.

3. Lowlevel-driver configuration.

   Configuration depends on how the drivers are built. See the

   README. for information on driver-specific setup.

4. Device-inodes

   The major and minor numbers and their names are described in

   Documentation/devices.txt. The major numbers are:

     43 for the ISDN-tty's.

     44 for the ISDN-callout-tty's.

     45 for control/info/debug devices.

5. Application

   a) For some card-types, firmware has to be loaded into the cards, before

      proceeding with device-independent setup. See README.

      for how to do that.

   b) If you only intend to use ttys, you are nearly ready now.

   c) If you want to have really permanent "Modem"-settings on disk, you

      can start the daemon iprofd. Give it a path to a file at the command-

      line. It will store the profile-settings in this file every time

      an AT&W0 is performed on any ISDN-tty. If the file already exists,

      all profiles are initialized from this file. If you want to unload

      any of the modules, kill iprofd first.

   d) For networking, continue: Create an interface:

       isdnctrl addif isdn0

   e) Set the EAZ (or MSN for Euro-ISDN):

       isdnctrl eaz isdn0 2

     (For 1TR6 a single digit is allowed, for Euro-ISDN the number is your

      real MSN e.g.: Phone-Number)

   f) Set the number for outgoing calls on the interface:

       isdnctrl addphone isdn0 out 1234567

       ... (this can be executed more than once, all assigned numbers are

            tried in order)

      and the number(s) for incoming calls:

       isdnctrl addphone isdn0 in 1234567

   g) Set the timeout for hang-up:

       isdnctrl huptimeout isdn0 

   h) additionally you may activate charge-hang-up (= Hang up before

      next charge-info, this only works, if your isdn-provider transmits

      the charge-info during and after the connection):

       isdnctrl chargehup isdn0 on

   i) Set the dial mode of the interface:

       isdnctrl dialmode isdn0 auto

      "off" means that you (or the system) cannot make any connection

        (neither incoming or outgoing connections are possible). Use

        this if you want to be sure that no connections will be made.

      "auto" means that the interface is in auto-dial mode, and will

        attempt to make a connection whenever a network data packet needs

        the interface's link. Note that this can cause unexpected dialouts,

        and lead to a high phone bill! Some daemons or other pc's that use

        this interface can cause this.

        Incoming connections are also possible.

      "manual" is a dial mode created to prevent the unexpected dialouts.

        In this mode, the interface will never make any connections on its

        own. You must explicitly initiate a connection with "isdnctrl dial

        sdn0". However, after an idle time of no traffic as configured for

        the huptimeout value with isdnctrl, the connection _will_ be ended.

        If you don't want any automatic hangup, set the huptimeout value to 0.

        "manual" is the default.

   j) Setup the interface with ifconfig as usual, and set a route to it.

   k) (optional) If you run X11 and have Tcl/Tk-wish version 4.0, you can use

     the script tools/tcltk/isdnmon. You can add actions for line-status

     changes. See the comments at the beginning of the script for how to

     do that. There are other tty-based tools in the tools-subdirectory

     contributed by Michael Knigge (imon), Volker Götz (imontty) and

     Andreas Kool (isdnmon).

   l) For initial testing, you can set the verbose-level to 2 (default: 0).

      Then all incoming calls are logged, even if they are not addressed

      to one of the configured net-interfaces:

      isdnctrl verbose 2

  Now you are ready! A ping to the set address should now result in an

  automatic dial-out (look at syslog kernel-messages).

  The phone numbers and EAZs can be assigned at any time with isdnctrl.

  You can add as many interfaces as you like with addif following the

  directions above. Of course, there may be some limitations. But we have

  tested as many as 20 interfaces without any problem. However, if you

  don't give an interface name to addif, the  kernel will assign a name

  which starts with "eth". The number of "eth"-interfaces is limited by

  the kernel.

5. Additional options for isdnctrl:

   "isdnctrl secure  on"

   Only incoming calls, for which the caller-id is listed in the access

   list of the interface are accepted. You can add caller-id's With the

   command "isdnctrl addphone  in "

   Euro-ISDN does not transmit the leading '0' of the caller-id for an

   incoming call, therefore you should configure it accordingly.

   If the real number for the dialout e.g. is "09311234567" the number

   to configure here is "9311234567". The pattern-match function

   works similar to the shell mechanism.

     ?     one arbitrary digit

     *     zero or arbitrary many digits

     [123] one of the digits in the list

     [1-5] one digit between '1' and '5'

           a '^' as the first character in a list inverts the list

   "isdnctrl secure  off"

   Switch off secure operation (default).

   "isdnctrl ihup  [on|off]"

   Switch the hang-up-timer for incoming calls on or off.

   "isdnctrl eaz "

   Returns the EAZ of an interface.

   "isdnctrl delphone  in|out "

   Deletes a number from one of the access-lists of the interface.

   "isdnctrl delif "

   Removes the interface (and possible slaves) from the kernel.

   (You have to unregister it with "ifconfig  down" before).

   "isdnctrl callback  [on|off]"

   Switches an interface to callback-mode. In this mode, an incoming call

   will be rejected and after this the remote-station will be called. If

   you test this feature by using ping, some routers will re-dial very

   quickly, so that the callback from isdn4linux may not be recognized.

   In this case use ping with the option -i  to increase the interval

   between echo-packets.

   "isdnctrl cbdelay  [seconds]"

   Sets the delay (default 5 sec) between an incoming call and start of

   dialing when callback is enabled.

   "isdnctrl cbhup  [on|off]"

   This enables (default) or disables an active hangup (reject) when getting an

   incoming call for an interface which is configured for callback.

   "isdnctrl encap  "

   Selects the type of packet-encapsulation. The encapsulation can be changed

   only while an interface is down.

   At the moment the following values are supported:

   rawip    (Default) Selects raw-IP-encapsulation. This means, MAC-headers

            are stripped off.

   ip       IP with type-field. Same as IP but the type-field of the MAC-header

            is preserved.

   cisco-h  A special-mode for communicating with a Cisco, which is configured

            to do "hdlc"

   ethernet No stripping. Packets are sent with full MAC-header.

            The Ethernet-address of the interface is faked, from its

            IP-address: fc:fc:i1:i2:i3:i4, where i1-4 are the IP-addr.-values.

   syncppp  Synchronous PPP

   uihdlc   HDLC with UI-frame-header (for use with DOS ISPA, option -h1)

   Watching packets, using standard-tcpdump will fail for all encapsulations

   except ethernet because tcpdump does not know how to handle packets

   without MAC-header. A patch for tcpdump is included in the utility-package

   mentioned above.

   "isdnctrl l2_prot  "

   Selects a layer-2-protocol.

   (With the ICN-driver and the HiSax-driver, "x75i" and "hdlc" is available.

   With other drivers, "x75ui", "x75bui" may be possible too.)

   isdnctrl l3_prot  

   The same for layer-3. (At the moment only "trans" is allowed)

   "isdnctrl list "

   Shows all parameters of an interface and the charge-info.

   Try "all" as the interface name.

   "isdnctrl hangup "

   Forces hangup of an interface.

   "isdnctrl bind  , [exclusive]"

   If you are using more than one ISDN card, it is sometimes necessary to

   dial out using a specific card or even preserve a specific channel for

   dialout of a specific net-interface. This can be done with the above

   command. Replace  by whatever you assigned while loading the

   module. The  is counted from zero. The upper limit

   depends on the card used. At the moment no card supports more than

   2 channels, so the upper limit is one.

   "isdnctrl unbind "

   unbinds a previously bound interface.

   "isdnctrl busreject  on|off"

   If switched on, isdn4linux replies a REJECT to incoming calls, it

   cannot match to any configured interface.

   If switched off, nothing happens in this case.

   You normally should NOT enable this feature, if the ISDN adapter is not

   the only device connected to the S0-bus. Otherwise it could happen that

   isdn4linux rejects an incoming call, which belongs to another device on

   the bus.

   "isdnctrl addslave  

   Creates a slave interface for channel-bundling. Slave interfaces are

   not seen by the kernel, but their ISDN-part can be configured with

   isdnctrl as usual. (Phone numbers, EAZ/MSN, timeouts etc.) If more

   than two channels are to be bundled, feel free to create as many as you

   want. InterfaceName must be a real interface, NOT a slave. Slave interfaces

   start dialing, if the master interface resp. the previous slave interface

   has a load of more than 7000 cps. They hangup if the load goes under 7000

   cps, according to their "huptimeout"-parameter.

   "isdnctrl sdelay  secs."

   This sets the minimum time an Interface has to be fully loaded, until

   it sends a dial-request to its slave.

   "isdnctrl dial "

   Forces an interface to start dialing even if no packets are to be

   transferred.

   "isdnctrl mapping  MSN0,MSN1,MSN2,...MSN9"

   This installs a mapping table for EAZ<->MSN-mapping for a single line.

   Missing MSN's have to be given as "-" or can be omitted, if at the end

   of the commandline.

   With this command, it's now possible to have an interface listening to

   mixed 1TR6- and Euro-Type lines. In this case, the interface has to be

   configured to a 1TR6-type EAZ (one digit). The mapping is also valid

   for tty-emulation. Seen from the interface/tty-level the mapping

   CAN be used, however it's possible to use single tty's/interfaces with

   real MSN's (more digits) also, in which case the mapping will be ignored.

   Here is an example:

   You have a 1TR6-type line with base-nr. 1234567 and a Euro-line with

   MSN's 987654, 987655 and 987656. The DriverId for the Euro-line is "EURO".

   isdnctrl mapping EURO -,987654,987655,987656,-,987655

   ...

   isdnctrl eaz isdn0 1      # listen on 12345671(1tr6) and 987654(euro)

   ...

   isdnctrl eaz isdn1 4      # listen on 12345674(1tr6) only.

   ...

   isdnctrl eaz isdn2 987654 # listen on 987654(euro) only.

   Same scheme is used with AT&E...  at the tty's.

6. If you want to write a new low-level-driver, you are welcome.

   The interface to the link-level-module is described in the file INTERFACE.

   If the interface should be expanded for any reason, don't do it

   on your own, send me a mail containing the proposed changes and

   some reasoning about them.

   If other drivers will not be affected, I will include the changes

   in the next release.

   For developers only, there is a second mailing-list. Write to me

   (fritz@isdn4linux.de), if you want to join that list.

Have fun!

 -Fritz