TCP/IP over ISDN. Frequently Asked Questions

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Jan-Piet Mens

Jun 11, 1996, 3:00:00 AM6/11/96

Version: $Revision: 1.4 $
Last-Modified: $Date: 1996/06/11 09:15:40 $
FAQ: de-isdn/tcp-ip
Posting-Frequency: monthly

TCP/IP over ISDN. Frequently Asked Questions
Jan-Piet Mens <>

This document describes methods which can be used to run TCP/IP and
related protocols over ISDN networks. Most of the software and proce-
dures described herein have only been tested on German 1TR6 or Euro-
ISDN (DSS1) networks.

Table of Contents:

1. Copyright, Version and availability

2. Introduction

2.1. Why TCP/IP over ISDN ?

2.2. What can I do with TCP/IP over ISDN ?

2.3. What possibilities do I have of running TCP/IP over ISDN ?

2.4. What solutions exist for use on an MS-DOS PC ?

2.5. What solutions exist for TCP/IP over ISDN based on Unix ?

3. Where can I get a connection to a POP (in Germany) ?

4. Software and configuration samples for creating a PC router

4.1. Hardware requirements

4.2. Software requirements

4.2.1. CAPI

4.2.2. Packet Drivers

4.2.3. ISPA

4.2.4. PCROUTE - an IP routing program for the IBM PC What is PCROUTE ? What does PCROUTE support ? IP-Adresses for PCROUTE My ISPA and PCROUTE configuration starts dialing
immediately without my interaction Tell me more about IP-addresses and PCROUTE How do I configure the needed routes on UNIX ? Sample configuration for ISPA and PCROUTE

4.2.5. ISPA and KA9Q

4.2.6. A fully functional router with all required files

4.3. How can I use two Teles.S0 ISDN cards in a PC-router ?

4.3.1. PAPI Packet Driver Howto use PAPI Sample configuration PAPI and PCROUTE

4.3.2. INS/CLS software ISDNPKT IPSWITCH Configuration tips Tested configurations

4.4. Other useful software

4.4.1. What is PCBRIDGE ?

4.4.2. How can I test my Packet-Driver/my ISPA ?

4.4.3. What is cFos (Fossil) ?

4.4.4. Are there free implementations of ISDN/IP for Unix/Linux ?

4.4.5. What is SLX ?

4.4.6. Where do I find ethernet packet drivers ? What ethernet cards have packet driver support ?

4.5. Where do I find ISDN hardware ?

4.6. CAPI error codes

5. Contact addresses

6. Resources for IP over ISDN

7. Where will I find the ISDN/IP FAQ ?

8. Contributors and Credits

9. Glossary

1. Copyright, Version and availability

This document is copyright (c) Jan-Piet Mens 1995, 1996.

Unless otherwise stated, all opinions herein are my own. The
descriptions, hints and tips have been gathered from all sorts of
sources. I have tried to give credit where credit is due. Should you
have contributed and feel left out, please drop me a line to be
included in the credits.

Contributions are very welcome!

This document is posted regularly to the newsgroup de.comm.isdn

Version: $Revision: 1.4 $
Last-Modified: $Date: 1996/06/11 09:15:40 $
FAQ: de-isdn/tcp-ip
Posting-Frequency: monthly
Archive-name: de-isdn/tcp-ip

2. Introduction

This document hopes to assist during the installation of TCP/IP over
ISDN (ISDN/IP). Our main topics will be routers and/or gateways
running under the MS-DOS or MS-Windows operating systems. The reason
for this, is that

o they are cheap and

o I operate one of these myself :-)

All internet addresses (IP adresses) and telephone numbers used in
this document are examples only. Never use one of these numbers.


Why TCP/IP over ISDN ?

The advantages of driving TCP/IP over ISDN for coupling hosts over WAN

o the transfer rate of 64Kbit/sec or over

o the fast connection times (< 2sec)

o line capacity only costs money while it is in use

o ISDN is undergoing an ever-increased use

2.2. What can I do with TCP/IP over ISDN ?

Everything :-)

telnet, ftp, nntp (NetNews), smtp (Mail), WWW, archie, X-Window
System, etc. As I said: everything.

2.3. What possibilities do I have of running TCP/IP over ISDN ?

The long list of methods of running TCP/IP over ISDN include free or
almost-free software running on a cheap PC through more expensive
commercial software routers for PCs and Unix systems, up to expensive
full-featured professional router systems (Cisco, etc.)

Traditionally the cheapest solution will be to use almost-free
software on a simple PC running the MS-DOS operating system. The
better method is of course to use professional software which usually
runs on Unix. The latter is usually more flexible and scales better.

When I started, I did not wish to invest over DEM 10,000.00 in a
software and hardware design to connect via ISDN to the Internet. I
wanted to start off cheaply before investing such amounts in
equipment. It turns out, that I still use the "cheap" version if only
because it still works for me (and hundreds of others).
2.4. What solutions exist for use on an MS-DOS PC ?

There are a miriad solutions for running TCP/IP over ISDN on MS-DOS.
Quite apart from the several commercial solutions, I have tested the
following combinations:


2.5. What solutions exist for TCP/IP over ISDN based on Unix ?

netCS offers a product suite called netGW and BinTec also has a suite
of software/hardware combinations that support TCP/IP over ISDN for
example for SCO-Unix.

See section ``Free ISDN/IP for Unix/Linux'' for more information.

3. Where can I get a connection to a POP (in Germany) ?

This is a list of Points of Presence or ISP that are willing to sell
connectivity to either private people or commercial institutions.

If you want to be included in this list, please send the following
form to ISDN-FAQ maintainer <>

Name of provider or ISP:
Tel (voice).......:
ca. DM/Month fix..:
ca. DM/MB National:
ISDN-access points:
Snail Mail........:

PFM News & Mail Mainz
Contact-Person....: Bernd Hennig
Tel (voice).......: 06131/362779
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Mainz
Snail Mail........: Eibenweg 4, D-55128 Mainz

Individual Network - Rhein-Main.DE
Contact-Person....: Oliver Boehmer
Tel (voice).......: 069/39048413
ca. DM/Month fix..: 40 DM
ca. DM/MB National: 3 DM

roka EDV und Datenkommunikationsberatung GmbH
Contact-Person....: Bernward Averwald und Wilhelm Buehler
Tel (voice).......: 02151/4975-10
Preise............: on request
ISDN-Access.......: Krefeld, Duisburg, Essen
ISDN-Access.......: Koeln-Porz, Aachen, Muenster
Snail Mail........: Elbestrasse 25, D-47800 Krefeld

prodata Ing.-Buero Neu-Ulm Xlink-PoP Ulm/Neu-Ulm
Contact-Person....: Juergen Mueller, Oliver Jung
Tel (voice).......: 0731/722426
ca. DM/Month fix..: on request
ca. DM/MB National: on request

AllCon Gesellschaft f. Kommunikationstechnologie mbH
Technologiezentrum Flensburg
Contact-Person....: Herr Dirks, Herr Jensen
Tel (voice).......: 0461-9992-162
ca. DM/Month fix..: on request
ca. DM/MB National: on request

Seicom GmbH
Xlink-POP Reutlingen
Contact-Person....: Winfried Haug / Peter Dieth
Tel (voice).......: 07121-9770-0
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Reutlingen, Tuebingen
Snail Mail........: Laiblinsplatz 12, 72793 Pfullingen

PEM Programmentwicklungsgesellschaft f Microcomp GmbH
Xlink-POP Stuttgart
Contact-Person...: Christoph Pasch
Tel. (Voice).....: 0711/713045
Fax..............: 0711/713047
email............: /
ca.DM/Month fix. : on request
ca.DM/MB National: on request
ISDN-Zugangspkte.: Stuttgart
Snail Mail.......: Vaihinger Str. 49, 70567 Stuttgart

netmbx, EUnet POP Berlin
Contact-Person....: Ralf Moritz
Tel (voice).......: 030-8555350
ca. DM/Month fix..: 20 DM + int. Volumen (+ IN Mitgliedschaft)
ca. DM/MB National: keine (10 DM/MB int. oder hoehere Fixkosten)
ISDN-Access.......: Berlin
Snail Mail........: Feuerbachstr. 47/49, 12163 Berlin

Noris Network
Contact-Person....: Matthias Urlichs
Tel (voice).......: 0911/9959621
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Nuernberg
Snail Mail........: Schleiermacherstr. 12, D-90491 Nuernberg

TouchNET GmbH i.Gr., Contrib.Net PoP Muenchen
Contact-Person....: Stefan Wei"s
Tel (voice).......: 089/54471111
DM/Month fix......: DM 115,00 (Waehlleitung, Zugang nur 16-9
DM 862,50 (Waehlleitung, 24h/Tag, 140h/Month)
DM 4025,00 (SPV, ohne Einschraenkungen)

ISDN-Access.......: M"unchen
Snail Mail........: Ringseisstra"se 2a, 80337 Muenchen

Freinet, Xlink-PoP Freiburg 2i Distribution & Solution GmbH
Contact-Person....: Dr. Monika Paulus, Florian Wolpert
Tel (voice).......: 0761-472850
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Freiburg
Snail Mail........: Haierweg 20e, 79114 Freiburg

Commercial Link Systems
Contact-Person....: Heiko Voland
Tel (voice).......: 0431 979 01 61
DM/Month fix..: 50 DM (25 DM Schueler/Studenten)
DM/MB National: keine Unterscheidung zwischen
3 MB IP in Grundgebuehr
zusaetzlicher Traffic: 0,02 DM/kB
(Verkehr zu ermaessigt)
ISDN-Access.......: Kiel
Snail Mail........: Sternstr. 2 , 24116 Kiel

MetaWorks Gesellschaft fuer elektronische und
audiovisuelle Medien mbH
Contact-Person....: Jens Hoffmann
Tel (voice).......: 0261/37773
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Koblenz

Inter Networking Systems
Contact-Person....: B. Hoenig
Tel (voice).......: 02305-356505
Tel (fax).........: 02305-25411
DM/Month fix..: 50 DM (Schueler/Studenten 25 DM)
DM/MB National: keine Unterscheidung national/international
3 MB IP in Grundgebuehr
zusaetzlicher Traffic: 0,02 DM/kB
Nutzungsbeschr....: keine Nutzungsbeschraenkung. Private und
kommerzielle Nutzung sowie Weitergabe erlaubt
ISDN-Access.......: Castrop-Rauxel, Essen, weitere in
Snail Mail........: INS, Postfach 101312, 44543 Castrop-Rauxel

Offenes Netz e.V. Luebeck
Contact-Person....: Wolfgang Fahl
Tel (voice).......: 0451/4998021
Email.............: in...@ON-Luebeck.DE
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Luebeck
Snail Mail........: Seelandstr. 3, 23569 Luebeck

ISC Dr.-Ing. Nepustil MAZ ISC Nuertingen
Contact-Person....: Dr. Ulrich Nepustil
Tel (voice).......: 07123-93102-0
Email ............:
ca. DM/Month fix..: on request (keine Grundgebuehr)
ca. DM/MB National: keine Unterscheidung National/International
Tariffierung erfolgt diensteunabhaengig
Verkehr zu ermaessigt
Nutzungsbeschr....: Keine Nutzungsbeschraenkung. Private und
kommerzielle Nutzung sowie Weitergabe nach
Vereinbarung erlaubt.
ISDN Access.......: Nuertingen / Reutlingen / Tuebingen

Contact-Person....: Holger Stegemann
Tel (voice).......: 069/619048
ca. DM/Month fix..: 50 DM
ca. DM/MB National: keine Unterscheidung national/international
News komplett sowie 1 MB IP in Grundgebuehr enthalten
zusaetzlicher Traffic: 0,03 DM/KB
Nutzungsbeschr....: Keine Nutzungsbeschraenkung. Private und
kommerzielle Nutzung sowie Weitergabe nach
Vereinbarung erlaubt.
ISDN-Access.......: Frankfurt, Dreieich, Darmstadt
Snail Mail........: Staedelstrasse 8, 60596 Frankfurt

CNet Internet Service Center
Contact-Person....: Bernd Pflugrad
Tel (voice).......: 0335/55586-0
ca. DM/Month fix..: on request
ca. DM/MB National: on request
ISDN-Access.......: Frankfurt (Oder)
Snail Mail........: Rudolf Breitscheid Strasse 10,
D-15230 Frankfurt (Oder)

This is a list of German universities and high schools willing to
offer connections to their students.

Technische Universitaet Berlin, FB Informatik
Contact-Person....: Carsten Rossenhoevel
Tel (voice).......: nein, verschont mich bitte :-)
ca. DM/Monat fix..: 0
ca. DM/MB National: 0
ISDN-Zugangspunkte: Berlin
Nutzungsbeschr....: Studierende/Mitarbeiter von Berliner
Gelbe Post........: Informatik-Rechnerbetrieb, Sekr FR 5-3
Franklinstr. 28/29, 10587 Berlin

Universitaet Konstanz, Rechenzentrum
Contact-Person....: Frank Bickendorf
Tel (voice).......: ?
WorldWideWeb......: http://www.uni-
ca. DM/Monat fix..: 0
ca. DM/MB National: 0
Nutzungsbeschr....: *Studierende* der *Uni* Konstanz
ISDN-Zugangspunkte: Konstanz

Universitaet Mannheim, Rechenzentrum
Contact-Person....: Joachim Nerz
Tel (voice).......: 0621-292-1433
ca. DM/Monat fix..: 0
ca. DM/MB National: 0
ISDN-Zugangspunkte: Mannheim
Nutzungsbeschr....: Studierende/Mitarbeiter der Uni-Mannheim
Gelbe Post........: Rechenzentrum Uni-Mannheim, L 15,16, 68131

4. Software and configuration samples for creating a PC router

This chapter describes required software and hardware for creating a
small router which is able to route packets between a TCP/IP Ethernet
lan and your Internet provider via ISDN.

The router will consist of a small and very cheap personal computer
running the MS-DOS operating system.

4.1. Hardware requirements

The hardware required for our router is minimal. A small personal
computer with, eg. Intel 386/SX processor would do fine. The computer
will only require a keyboard and a screen for setting up the software.
During operation, neither a monitor nor a keyboard is required.

Mass storage
A floppy disk drive with a capacity of 1.44MB is all that is
required for operation. Of course, if your small PC comes with a
disk, all the better, but it is not required.

Network Interface
The computer will require a network interface card (NIC). Any
low-cost NIC will do fine, for example an NE2000 or WD8003
compatible. In principle, any card supported by the Clarkson
Packet Drivers will do.

ISDN card
An inexpensive ISDN card will be required to connect to the ISDN
network. I personally use the original Teles S0 card, which at
the time was one of the least expensive. It is a passive card
but produces enough throuput for our requirements. I understand
that Creatix sells a Teles.S0 compatible card. In principle, any
card that comes with a CAPI 1.1 interface should do the trick.

4.2. Software requirements

The following software will be used on our router:

CAPI is the Common ISDN Application Programmers Interface. This
software is supplied together with the ISDN card.

Packet Driver
Freeware. A packet driver from the Clarkson Packet driver
collection will be required to interface with our NIC.

Shareware. ISPA is an ethernet-type packet driver which loads on
top of a CAPI and delivers a packet-driver interface.

Freeware. This is the software that will do the actual routing.
It will move IP packets from the packet driver on the NIC to the
packet-driver on the ISDN card.

As an alternative to PCROUTE, KA9Q can be used as well. Please
note that KA9Q has certain usage restrictions. Check the docs.

4.2.1. CAPI

Common ISDN Application Programming Interface. It is a programming
interface similar to NetBios and it runs between application software
(ISPA, PAPI, etc) and the CAPI device driver (ISDN card) on a PC.

A CAPI is usually supplied by the manufacturer of the ISDN hardware,
and it is a requirement for anything encountered in this document.

4.2.2. Packet Drivers

4.2.3. ISPA

ISPA is an ethernet-type (class=1) packet-driver for IP-Routing or
remote Ethernet bridging over ISDN. ISPA communicates with the ISDN
card using the ISDN API 1.1 specification (a standard defined by
German ISDN card manufacturers and the German Telekom). Because of
this, ISPA is completely hardware independent and has successfully
been tested with many active and passive ISDN cards.

ISPA was initially developed for use with PCROUTE as a cheap Ethernet-
ISDN Router. However, it is more and more used to connect a standalone
PC system to the Internet using ISDN. For easy use under Windows ISPA
comes with a Windows utility program ISDNMON. ISPA has successfully
been tested with a wide range of commercial, shareware and public
domain TCP/IP packages e.g. Ftp PCTCP, Sun PC-NFS, Novell LanWorkPlace
and PDETHER, WATTCP based IP programs, NCSA & CU -Telnet/ftp, UMN
gopher & popmail Trumpet WINSOCK, XFS.

ISPA is shareware. It will stop operation after about 15 minutes
unless you register it. ISPA can be retrieved from

Note that Herbert Hanewinkel, the author of ISPA, frequently adds
features to ISPA and its sort. It is worthwhile checking his ftp
server on a regular basis. I personally have found him to be very
helpful in sorting out "features" :-)

4.2.4. PCROUTE - an IP routing program for the IBM PC

PCROUTE - an IP routing program from the IBM PC Vance Morrison

There seem to be differing versions. The newest I know of is 2.24. What is PCROUTE ?

PCroute is software written for an PC/XT (or AT) or clone that will
allow it to act as a IP router. At present the following interfaces
are supported.

(WD8003E card) (recommeded no more than 4 interfaces)

(WD8003S card) (up to 6 interfaces)

(Apple localtalk card for the PC) (1 interface max)

(COM1..COM4) (2 interfaces max) What does PCROUTE support ?

PCroute was designed to be a fully functional IP router. In particular
it supports

o IP routing with Subsets (however the subnet mask must begin with

o Static routing with up to 250 routes.

o responds to ICMP echo (ping)

o Sends ICMP TTL, Redirect, Unreachable when appropriate

o Fragmentation where necessary

o RIP dynamic routing protocol

o Up to 6 interfaces of varying types

o Error logging using BSD syslog

o Optional proxy ARP

o Bootp forwarding

o Packet-Driver interfaces

Note that although the software supports up to 6 interfaces, the total
throughput of the router is fixed by the speed of the processor. For
fast boards (ethernet) this gets excessive after 4 interfaces are

PCROUTE can be found on IP-Adresses for PCROUTE

The following texts where produced in German. I have taken the liberty
of translating them... (JPM)

From: (Winfried Haug)
Newsgroups: de.comm.isdn

| IMPORTANT: PC-Route needs 2 IP addresses out of 2 different Class C
| networks. Router and Ethernet IP-adress may not be in the same net.
| A router usually requires 2 addresses otherwise no routing occurs.

From: heha
If I only route to one partner then I can route over an interface. If
I have more than one partner then routing must occur over IP-addresses.
Since PCroute was developed as an Ethernet-router with several
partners per interface, it must route via IP-addresses. My ISPA and PCROUTE configuration starts dialing immediately
without my interaction

Wrong. ISPA only starts dialing if packets are outstanding for the
remote connection. If PCROUTE is configured with RIP support (FLAGS =
0x) then an RIP packet will go out every 30 seconds and this would
cause an otherwise idle ISPA to dial. Tell me more about IP-addresses and PCROUTE

From: (TZ Juergen Mueller)

+-------------------------------+ +--------------+
isdn||ethern| |
WORLD<--->| |<---->| |
+-------------------------------+ +--------------+

DOS requires IP-addresses of two different networks otherwise it won't
be able to route. The right side of the (dos)-IP's should be The destination route for PCRoute should thus be the
left of the two addresses (IP address of the router on the far side of
the ISDN wire) How do I configure the needed routes on UNIX ?

# route add default (see above)
# route add Sample configuration for ISPA and PCROUTE

C:\> type isdn.bat
call c:\telescom\starts0 : Load CAPI

wd8003e 0x60 0x7 0x300 0xcc00 : Load packet driver
: : : :
: : : +------ Ram Base
: : +------------ Base address
: +----------------- HW-IRQ of the WD-Ethernet card
+--------------------- Software IRQ

ispa -e 4 -t 120 -h 1 0x61 0691234567 : ispa laden
: : : : :
: : : : +- Called number
: : : +------- ISPA's SW-IRQ (see. wd8003e)
: : +----------- HDLC-Framing (see ispa.doc)
: +----------------- timeout (see ispa.doc)
+----------------------- Incoming calls on EAZ=4

pcroute : Load pcroute

Before loading pcroute, the PCROUTE.CFG file must be created by using
config.exe. I am asked for 2 interfaces. The first interface must be
located on SW-IRQ 0x60 the second interface is located on sw-irq 0x61.
Since we loaded the wd8003e on 0x60 and ispa was loaded on 0x61,
interface-1 is Ethernet and interface-2 is on ISDN.

C:\> type pcroute.cfg (is created with config.exe)
Interface 1 (ethernet)
Flags 0000H
Metric 0000H
Interface 2 (ethernet)
Flags 0000H : Flags = 0 means "Send
: Routing updates out
: this interface", this
: would case a RIP
: packet each 30 secs.
: and ISPA starts dialing
Metric 0000H
The Ethenet Address 0000H
The Ethenet Address FBAAH
The Ethenet Address 0061H : 0x61
Route to network : default route
Through gateway
Metric 0000H
Flags 0000H

Route to network
Through gateway
Metric 0000H
Flags 0000H

Forwarding BOOTP requests to
Logging messages to SYSLOGD on host
Logging level 0009H : A message per minute
Logging mask 0000H

4.2.5. ISPA and KA9Q

C:\> type isdn.bat
call c:\telescom\starts0 : Load CAPI

wd8003e 0x60 0x7 0x300 0xcc00 : Load packet driver
: : : :
: : : +------ Ram Base
: : +------------ Base address
: +----------------- Hardware IRQ
+--------------------- Software IRQ

ispa -e 4 -t 120 -h 1 0x61 0691234567 : Load ISPA
: : : : :
: : : : +- ISDN number to call
: : : +------- SW-IRQ of ISPA (see. wd8003e)
: : +----------- HDLC-Framing (see ispa.doc)
: +----------------- timeout (see ispa.doc)
+----------------------- Receive calls on MSN 4

net : Load KA9Q

C:\> type
# KA9Q configuration file
hostname rter

# 0x60 = sw-irq of NIC
attach packet 0x60 eth 10 1500
ifconfig eth ipaddress broadcast
ifconfig eth netmask 0xffffff00

# 0x61 = sw-irq of ISPA
attach packet 0x61 isdn 10 1500
ifconfig isdn ipaddress broadcast
ifconfig isdn netmask 0xffffff00

route add eth
route add isdn
route drop
route add default isdn

4.2.6. A fully functional router with all required files

In this section you'll find all required files for a fully functional
router based on a Teles.S0 card, a WD8003 Ethernet card. This router
connects a network of Unix and MS-Windows systems (Windows 95, Windows
NT) to the Internet.






: Start TELES/S.0 CAPI driver
call c:\telescom\starts0h.bat

: Load Packet Driver on SW-IRQ = 0x60
smc_wd 0x60 0x4 0x300 0xcc00

: Load ISPA on SW-IRQ = 0x61
ispa304 <registration-key> 0x61 ispa.ini

: Start KA9Q/NOS with root directory in /
nos11c-a -d/


# ispa.ini
# Configuration file for ISPA 3.x on gateway
-e2 # EAZ 2 (my MSN)
-w # Display activity
-r193.37.22.49, # Loghost, myip 05123683012 -h1 -t220 -d3 # Callback 05123683002 -h1 -t220 -d3 # Callback (2nd no.) 05123683282 -h1 -t220 -d3 # Callback (3rd no.)


## KA9q NOS version (N1BEE 921225v0.85s-beta) (CWRU/BIOGv 1.92 - axa12)
## configured by
isat on
ip address
domain suffix

## domain nameserver (DNS) configuration
domain addserver
domain verbose on
domain translate off # don't turn name translation on
domain cache size 20
domain cache wait 300
domain retry 1
domain maxwait 90

## HOST interface configuration - WD8003 card with packet driver
attach packet 0x60 lan 10 1500 # packet driver at 0x60, 5 buffers, MTU=1500
ifconfig lan ipaddr netmask 0xfffffff0 broadcast

## ISDN configuration. ISPA on packet-driver-interrupt 0x61

attach packet 0x61 isdn 10 1500 # packet driver at 0x61, 5 buffers, MTU=1500
ifconfig isdn ipaddr netmask 0xffffff00

## Route all packets to MENS-NET (.48) onto interface `lan'.
route add lan

## Add a default route to interface `isdn'. This I route via,
## because it is the address on which ISPA is listening for packets.
route add default isdn 1

# TCP/IP parameters
ip rtimer 60
ip ttl 255
tcp window 2048
tcp mss 1460
tcp irtt 10000

4.3. How can I use two Teles.S0 ISDN cards in a PC-router ?

From: "Alexander Horn"
(translated by JPM)

C:\TELESCOM\TSRKRN 8192 # Buffer in Bytes (*Important*)
C:\TELESCOM\S0TE 0 3 c800 1 5 d000 # Controller 0: IRQ 3,
# Ram address: C800
# Controller 1: IRQ 5,
# Ram address: D000
C:\TELESCOM\HDLC 0 1 # HDLC for Controller 0 and 1
C:\TELESCOM\1TR6TE 0 1 # 1TR6-Hack for Controller 0 and 1

Konfiguration mit ISPA 1.8.1 & PC-Route bzw. INS/CLS-Software im
Dauerbetrieb getestet!

BTW, CAPI.EXE can be loaded in upper memory ... BUNDLE.EXE V110.EXE
and ISO8208.EXE do not support more than one controller That's it...
and then start S0STAT.EXE and relax...

4.3.1. PAPI Packet Driver

PAPI is a Packet driver for the isdn common API. It is an MSDOS TSR.
The Common ISDN API (ISDN-CAPI) is an interface defined by German
telecom and german ISDN Cards manufacturer. The ISDN-CAPI supported
is version 1.1, Profile A of 7.Sep.90 The packet interface implemented
is version 1.09. The implemented class is slip.

The newest version will always be available through If you do not
have access to ftp use their mail server: send mail to archive- and place the keyword help in the body of the

History - Why I wrote it: I use a small 286 MSDOS box as a router to
the Internet (EUNET). The box is equipped with an ISDN card and an
ethernet card. It connects my small network to the EUNET-POP via
ISDN. The packet driver which came with the first ISDN board was not
very stable.

I found a not too expensive ISDN board from teles Berlin. Their
software interface is the ISDN-CAPI. The board is very simple (only
two chips from Siemens). It is not intelligent (i.e. it does not have
a processor on board).

I use ka9q and pc-route as routers. The only part missing was a piece
of software interfacing ISDN-CAPI and ka9q. ka9q supports the packet
driver interface very well. papi is the missing link.


o only 1 application registered per program.

o only 1 controller supported per computer.

o only 1 papi packet driver per computer

o only 1 ISDN destination and the destination is fixed at the time
the driver is invoked.

o a tcp/ip packet has to be <= 2K

o only X75 and HDLC-UI frames as supported level 2 protocols.

o only tested with ka9q

It works now with Dr. Neuhaus Niccy 3008 and Niccy 1000 cards. With
AVM-A1 and Teles S0 Boards. I did not get to make the packet driver
work stable with the Diehl implementation of the CAPI. It might be the
problem of my packet driver. Anyway they sell their own packet
driver. The packet driver is exercising the interrupt scheme of a
CAPI. It is working in a heavily interrupt driven environment.

Howto use PAPI

First install the CAPI Interface you get with the ISDN-Card. Then
install papi. It is a Terminate and Stay Resident (TSR) program. Then
install the application you want to use i.e. ka9q.

Installation of papi:

papi [-v] [-x] [-u] [-o eaz] -n telno [ -N telno1 ]
[-p PacketIntNo] [-c CAPIIntNo] [-w Timeout] [-s BufSize]
[ -S BufSize1 ]

-v The packet driver is verbose when installing.

The packet driver is writing a status into line LN of the
display. Status resembles the display of an ISDN-Telephone.

-x Layer 2 protocol X75

-u Layer 2 protocol UI-HDLC Frames (default)

-c INT
Soft interrupt of ISDN-CAPI (default 0xF1)

-p INT
Soft interrupt of papi (default 0x60)

-o eaz
The digit which selects calls to your card. (default 2). Has to
be between 1 and 8.

-n ISDN#
The ISDN number of the host you want to connect to. This is the
only host which may call back. If you do not give a number papi
is not installed. If the host is not identifying himself with
his number when calling the call is not accepted! If you want
to use Semi Permanent Circuits add an 's' to the number. The
ISDN number is not checked. It is passed directly to the capi.

The ISDN number of the host as it is given from the network.
Under certain conditions the number coming from the network is
different from the number you have to dial. The packet driver is
using this number as a sort of password.

-i ignore. Do not check the incoming caller id.

-w n
The line is disconnected when idle for n seconds. (default 10)

-s bytes
maximal size for ip packets ( default and maximum 2048). The
actual maximum for NICCY 3008 is 1024.

-S bytes
size used for b2 protocol size.

-P The driver is working in a sort of polling mode. I.e. instead of
handling the incoming message in the interrupt only a mark is
set and the message is handled later in a timer interrupt. The
AVM-A1 Board is only working with this option.


# start the capi for your card:
# start the packet driver:
c:\capi\papi -v -n 123456 -o 3 -w 240 -u -c 0xF1 -p 0x60 -s 2048
# start your application (i.e. ka9q):
c:\nett\net -d c:\nett c:\nett\

More reasonable is:

c:\capi\papi -n 123456 -w 240

Comments, Questions, Error Reports, Support, Consulting ...: Sample configuration PAPI and PCROUTE

I don't know where this comes from (broute.tar ???)

A:\> type a:\autoexec.bat
COMMAND /C a:\teles\starts0.bat
a:\papi -V -v -p 0x61 -n 54990403 -N 06954990403 -o 3 -w 100 -s 2048
a:\papi -V 1 -v -p 0x62 -n 54990404 -N 06954990404 -o 4 -w 100 -s 2048
a:\wd8003e 0x60 -o 10 0x240 0xc800

A:\> config : pcroute config.exe
Address for the interface []
Subnet mask for the interface []
Flags (Hex) [5H]
Routing Metric (HEX) [1H]

Address for the interface []
Subnet mask for the interface []
Flags (Hex) [bH]
Routing Metric (HEX) [1H]

Network []
Gateway []
Metric [9H]
Flags [0H]

Network []
Gateway []
Metric [9H]
Flags [0H]

Address to forward bootp packets []
Host to send logging info to []
Logging mask [0H]
Logging Level [0H]

4.3.2. INS/CLS software

Eine kommerzielle Loesungen bieten die Firmen INS (Inter Networking
Systems) und CLS (Commercial Link Systems). Siehe (Adressen)

Die Loesung dieser beiden Firmen ist identisch und besteht aus einen
Packet Driver (ISDNPKT) und einen IP-Router (IPSWITCH) sowie einen
Line-Monitor (ISDN-MAN) mit Online-Display und Protokollierung in

ISDNPKT kostet 178,00 inkl. MwSt IPSWITCH kostet 348,00 inkl. MwST
ISDNPKT + IPSWITCH Bundle: 498,00 inkl. MwSt. ISDNPKT + IPSWITCH +
TELES.S0 Bundle 888,00 DM inkl. MwSt

Das "PLUS"-Paket, inkl. SNMP (MIB-II + Herstellererweiterungen),
verfuegbar ab CeBIT 94: ISDNPKT + IPSWITCH+ + TELES.S0 Bundle:
1.398,00 DM inkl. MwSt. beinhaltet kostenlosen Upgrade auf die PLUS-
Version des ISDNPKT, die Mitte April verfuegbar sein wird. ISDNPKT

ISDNPKT ist ein Packet-Driver fuer PC-ISDN Adapter. Die Kommunikation
mit der ISDN-Karte erfolgt ueber eine CAPI-Schnittstelle. Der DOS-
Anwendung gegenueber stellt ISDNPKT eine Ethernet Packet-Driver
Schnittstelle zur Verfuegung.

Unterstuetzt zwei ISDN-Adapter im System. 4 B-Kanaele, SPV, Gruppe 0
Typ 4 (mit TELES.S0) 30 Gegenstellen, Dedizierte
eingehende/ausgehende/bidirektionale Leitungen Automatisches Callback
Alternative Rufnummern fuer Gegenstellen "Short Hold" (idle timeout)
kann dynamisch an Laenge der Gebuehreneinheiten angepasst werden. IPSWITCH

IPSWITCH hat einen eigenen IP-Stack und routet zwischen Packet-Drivern
(vergl. PCROUTE). Alle Netzwerkadapter, fuer die Packet-Drivern
erhaeltlich sind, koennen eingesetzt werden. IPSWITCH erlaubt das
Monitoren von IP, ARP, TCP, und UDP sowie (seit Version 3.0)
accounting. RIP (Routing Information Protocol) Im Bundle mit ISDNPKT:
Nach festgelegter Anzahl fehlgeschlagener Waehlverbindungen wird Route
als "down" markiert (und propagiert). Source-abhaengiges Routing
moeglich IP-Paketfilterung (fuer Firewall) nach Source, destination,
Protokoll, Port In der PLUS-Version: SNMP (MIB-II und
Herstellererweiterungen) Remote Konfiguration Configuration tips

Hier sollte mal etwas *sinnvolles* stehen. Hat nicht einer der Herren
Heinen oder Frackowiak Lust dazu ;-

"Lust schon... Zeit erst nach der CeBIT 94 :(" Tested configurations

: ip.bat
: Start the Teles CAPI, a PacketDriver on my WD Ethernet followed by
: a PacketDriver for ISDNPKT
call c:\telescom\starts0.bat
wd8003e 0x60 0x7 0x300 0xcc00
isdnpkt -v
isdnman -d
ipswitch -v -l -p 6 -m jpisdn -t 60 -a

# isdnpkt.cfg Configuration file for ISDNPKT
# This file is shown with \ separating lines. Never the less, a
# configuration entry must be on *ONE* line.
#irq Name Prot direct contro other number match EAZ\
Serv. S.add Retries Down idle_in idle_o use_dy Frag wsize\
laAin laBin laAout laBout B2-IN B2-OUT B3-IN B3-OUT
61 isdnpfm IP B 0 07131834052 0000 4\
07 00 4 180 110 110 1 2000 7\
3 1 3 1 102 102 4 4

Anschliessend, haben wir auf irq=0x60 ethernet, und auf irq=0x61 den
isdnpkt. Diese nummern gelten entsprechend in den folgenden Files.

# ipswitch.if Interface Configuration for IPSWITCH
#irq use-arp ip-adress broadcast netmask
# local ethernet
60 0 ff.ff.ff.00
# isdn-interface
61 1 ff.ff.ff.ff

# ipswitch.rt Routing table for IPSWITCH
# Thanks to *and* for their help on a Saturday
# evening ;-)
# Note, how irq=0x60 is routed to the ethernet and the default route
# goes out to isdn.
# Network Routes
60 0 ff.ff.ff.ff
61 0

4.4. Other useful software

This section lists software that may be useful in the contect of
building a router.

4.4.1. What is PCBRIDGE ?

PCBRIDE allows a PC to be used as a bridge. As with PCroute there is
built-in support for WD/SMC and packet drivers as well as SLIP.

4.4.2. How can I test my Packet-Driver/my ISPA ?

For example with WatTCP (Waterloo TCP). Either start a Packet-Driver
or an ISPA on any sw-IRQ. With the following sample configuration you
can try and ping.

C:\> type wattcp.cfg
print="Sample configuration file"
nameserver= : not compulsory : not comulsory

C:\> wd8003e 0x60 0x2 0x280 0xd000 : load PacketDrv
C:\> ping : ping.exe


C:\> ispa .....
C:\> ping : ping.exe

4.4.3. What is cFos (Fossil) ?

cFos, by M. Winkler, C. Lueders

cFos is an ISDN CAPI FOSSIL driver. It was written to allow FIDO
compatible BBS, mailer software and FOSSIL supporting
terminalprograms to easyly communicate via ISDN. It also has a
build-in INT 14h emulator. A list of programs that work with cFos
can be found in the appendix of CFOS.DOC.

See COPYING.CF/LICENSE.DOC for warranty and licensing terms, see
WHATSNEW for a revision history.

Some features:

o uses the CAPI to access the ISDN hardware; thus very flexible

o is optimized for HIGHEST transfer speed: 7900cps!

o supports multiple ISDN channels in one driver

o supports both X75 and V110

o has it's own AT command emulator; looks like a standard modem to
the application

o has it's own superfast channel bundling, which is manufacturer
independant with up to 4 B-channels resulting in more than 30k
Bytes per second (we tested it !)

The most recent version of cFos may be obtained at...

Zaphods BBS, Bonn/Germany, Sysop Chris Lueders

+49-228-262894 14400bps, HST/V32b (fido 2:2453/30)
+49-228-9111041 64000bps, X75/V110 (fido 2:2453/33)

German Internet : Directory:
GAK.RHEIN.DE [] pub/isdn
FTP.DFV.RWTH-AACHEN.DE [] /pub/network/isdn/cfos

German CompuServe:

See the TELECOM forum, area Data/ISDN or,
see the GERNET forum, area Telecommunication.

Christoph Lueders Martin Winkler
Fidonet: 2:2453/30.1 2:2453/30.6

4.4.4. Are there free implementations of ISDN/IP for Unix/Linux ?

Yes. Two packages that I know of exist. They are:

Linux-ISDN package of Matthias Urlichs <>
Documentation in the German language only.

isdn4linux by Fritz Elfert <> and
Jan den Ouden
Isdn4linux consists of a link-level-module, low-level-module for
ICN ISDN-cards and a low-level-module for Teles-Cards by Jan den
Ouden. Available at
Documentation and instructions are in English and German.

4.4.5. What is SLX ?

SLX is a packet driver that uses the serial line as an interface.
Contrary to SLIP the whole ethernet frame including destination and
source addresses as well as the type field are transferred. This has
the advantage that one is independant of the IP protocol requires an
individual ethernet address though. Available from:

RzK Doris Koepke Fax: 0 2683 4537
Postfach 1200 70126,
53563 Asbach Ww.

for DEM 25,- (Single license).

4.4.6. Where do I find ethernet packet drivers ?

From Crynwr. If you are using Ethernet hardware you can probably find
free packet drivers for your cards via anonymous ftp to or in What ethernet cards have packet driver support ?

This list was extracted from the README for

3C501.COM Driver for 3COM 3C501.
3C503.COM Driver for 3COM 3C503.
3C505.COM Driver for 3COM 3C505.
3C507.COM Driver for 3COM 3C507.
3C523.COM Driver for 3COM 3C523.
AR450.COM Driver for Telesystems SLW ARLAN 450.
ARCETHER.COM Driver for ARCNET simulates an Ethernet driver.
AT&T.COM Driver for AT&T Ethernet and Starlan.
AT&T_LP.COM Driver for AT&T LanPACER/StarStation.
DAVIDSYS.COM Driver for David Systems Inc Ether-T.
DE600.COM Driver for D-Link Pocket LAN Adapter.
DEPCA.COM Driver for Digital Equipment DEPCA.
EN301.COM Driver for Multitech EN-301.
ETHERSL.COM Driver for SLIP that emulates an Ethernet driver
ETHIIE.COM Driver for ICL EtherTeam16
EXP16.COM Driver for Intel EtherExpress.
EXPRESS.COM Driver for Mitel Express ISDN adapter.
HPPCLAN.COM Driver for HP EtherTwist.
IBMTOKEN.COM Driver for IBM Token Ring Adapter.
IPXPKT.COM Driver for Novell IPX code (IP over IPX).
ISOLAN.COM Driver for BICC Isolan 4110-0.
ISOLINK.COM Driver for BICC Isolan 4110-2/3.
LOCALTLK.COM Driver for Apple LocalTalk PC Card, Sun/TOPS
NB.COM Driver for NetBIOS.
NCRET105.COM Driver for NCR ET-105.
NE1000.COM Driver for Novell NE1000.
NE2.COM Driver for Novell NE/2.
NE2000.COM Driver for Novell NE2000.
NI5010.COM Driver for Interlan NI5010.
NI5210.COM Driver for MICOM-Interlan NI5210.
NI6510.COM Driver for Racal/Interlan NI6510.
NI9210.COM Driver for MICOM-Interlan NI9210.
NTI16.COM Driver for NTI 1002/DP-16.
SLIP8250.COM Driver for SLIP driver using IBM-PC 8250.
TIARA.COM Driver for Tiara LANcard/E.
UBNICPC.COM Driver for Ungermann-Bass PC/NIC.
UBNICPS2.COM Driver for Ungermann-Bass NIC-PS/2.
WD8003E.COM Driver for Western Digital WD-8003e.

4.5. Where do I find ISDN hardware ?

At BinTec and netCS. (see: Addresses). You will also find hardware
ISDN cards at Teles, Diehl and many more.

4.6. CAPI error codes

Here is a list of CAPI error codes, extended by the V.110 error codes.

0x0000: No error

0x1001: Error on API_REGISTER
0x1002: Illegal application-id
0x1003: Illegal message
0x1004: Illegal command or subcommand
0x1005: Queue is full
0x1006: Queue is empty
0x1007: Queue overflow
0x1008: Deinstall error
0x1009: Windows address error

0x2001: Illegal Controller
0x2002: Illegal PLCI
0x2003: Illegal NCCI
0x2004: Illegal type

0x3101: B-channel erroneous
0x3102: Infomask erroneous
0x3103: Serviced-EAZ-mask erroneous
0x3104: Serviced-SI-mask erroneous
0x3105: Illegal B2 protocol
0x3106: Illegal DLPD
0x3107: Illegal B3 protocol
0x3108: Illegal NCPD
0x3109: Illegal NCPI
0x310A: Illegal flags

0x3201: General controller error
0x3202: non-unique LISTEN_REQs
0x3203: function not supported
0x3204: PLCI inactive
0x3205: NCCI inactive
0x3206: B2 protocol not supported
0x3207: can't select B2 protocol now
0x3208: B3 protocol not supported
0x3209: can't select B3 protocol now
0x320A: illegal DLPD parameters
0x320B: illegal NCPD parameters
0x320C: illegal NCPI parameters
0x320D: data length not supported

0x3301: D channel layer 1 setup error
0x3302: D channel layer 2 setup error
0x3303: B channel layer 1 setup error
0x3304: B channel layer 2 setup error
0x3305: D channel layer 1 shutdown
0x3306: D channel layer 2 shutdown
0x3307: D channel layer 3 shutdown
0x3308: B channel layer 1 shutdown
0x3309: B channel layer 2 shutdown
0x330A: B channel layer 3 shutdown
0x330B: B channel layer 2 reestablished
0x330C: B channel layer 3 reestablished

0x3400: Normal disconnect, no cause given by network
0x3480: Normal disconnect, no cause given by network
0x3481: Invalid CR value
0x3483: Bearer service not implemented
0x3487: Unknown caller identity
0x3488: Call Identity already suspended
0x3489: No channel available
0x348a: No channel available
0x3490: FAC Code unknown in this network
0x3491: requested service rejected
0x34a0: Outgoing calls barred
0x34a1: User access busy
0x34a2: Nonexistent CUG
0x34a3: Nonexistent CUG
0x34A5: Invalid or unknown destination
0x34b5: Destination not obtainable
0x34b8: Number changed
0x34b9: Out of order
0x34ba: No user responding
0x34bb: User busy
0x34bd: Incoming calls barred
0x34be: Call rejected
0x34d8: Invalid destination address
0x34d9: Network congestion
0x34da: Remote user initiated
0x34f0: Local procedure error
0x34f1: Remote procedure error
0x34f2: Remote suspended
0x34f3: Remote not suspended
0x34ff: Local reject of User to User info

0x4001: Stollmann: too many applications
0x4002: Stollmann: block size too large
0x4003: Stollmann: error on init of message queue
0x4004: Stollmann: no PLCI cntl block available
0x40ff: Stollmann: function not allowed in current context

0x4101: Verlust der Frame-Synchronisation

0x4201: Stollmann: can't deinstall, not on top of int chain
0x4202: Stollmann: can't deinstall, application still active

5. Contact addresses

This list of contact addresses is designed to help in contacting
individual providers of software and/or hardware for running TCP/IP
over ISDN.

INS Christa Keil & Andreas Frackowiak GbR
Gaswerkstrasse 11
44575 Castrop-Rauxel
Tel: 02305-356505
Fax: 02305-25411

CLS Wiljo Heinen
Sternstrasse 2
24116 Kiel
Tel: 0431-9790161
Fax: 0431-978126,

Kurfuerstendamm 207-208
10719 Berlin
Telefon: 030-8847-30
TeleFAX: 030-8847-31

netCS Informationstechnick GmbH
Feuerbachstr. 47/49
12163 Berlin 41
Tel: 030-856999-0
Fax: 030-8555218

PEM Programmentwicklungsgesellschaft fuer Microcomp. mbH
Vaihingerstrasse 49
70567 Stuttgart
Tel: 0711-713045
Fax: 0711-713047

BinTec Computersysteme GmbH
Willstaetterstrasse 30
90449 Nuernberg
Tel: 0911-9673-0
Fax: 0911-6880725

Dr. Herbert Hanewinkel
Max-Planck-Institut fuer Biochemie
D-82143 Martinsried
Tel.: (+49)89/8578-2735
Fax : (+49)89/8578-2479

6. Resources for IP over ISDN

This section lists resource locations and documents that may help in
setting up an ISDN line or in setting up anything based on ISDN :-)

comp.dcom.isdn FAQ

Frequently asked questions about ISDN

Die ISDN Seiten (the ISDN pages)

ISDN on Windows 95
Excellent! Driver and software (CAPI) for use on Windows 95.

Drivers and programs for ISDN (WIN95)

ISDN and Windows FAQ (German)
by Andreas Kuckartz <> is available at


Where will I find the ISDN/IP FAQ ?

The FAQ is posted periodically to the de.comm.isdn, de.comm.internet,
and de.answers newsgroups.

You can also contact the FAQ maintainer by mail at

8. Contributors and Credits

Here is a list of the contributors to this document. I hope the
credits are correct. (Herbert Hanewinkel) (Winfried Haug) (Dietmar Friede) (Matthias Watermann) (Joachim Astel) (Christoph Lueders) (Martin Winkler) (Oliver Boehmer) (Juergen Mueller) (Wolli Steiner) (Henrik Hempelmann)
Wilhelm Buehler <>
Franz Koepke <>
Oli Kai Paulus <> (Carsten Rossenhoevel)

These pages where formatted from an SGML source using the Linuxdoc-

9. Glossary

Bitratenadaption, definiert bis 9600 Baud; verfuegbar bei den
meisten Terminaladaptern bis 38400, z.T. auch bis 57600 Baud
Jedes Bit auf der V24 bzw. X21.bis Seite wird in ein Bit des
64kBit-Stromes des B-Kanals abgebildet. Bei einigen Implemen-
tierungen koennen langsamere Geschwindigkeiten gemultiplext
werden; d.h. es gibt mehere gueltige Abbildungen.

Aehnlich V110, jedoch zusaetzliches Entfernen von Start- und
Stop-bits im B-Kanal-Datenstrom. Daher ist die theoretische
moegliche Datenrate (ohne Komprimierung) 76800 Baud.

Aehnlich X25. Auf dem B-Kanal werden HDLC-Frames verschickt, die
numeriert, bestaetigt und moeglicherweise an mehrere Prozesse
geroutet werden muessen.

Ein Ethernet Frame wird als ein HDLC-Frame auf den B-Kanal
abgebildet. Das ist sehr effektiv, setzt aber voraus, dass der
Frame als solcher gleich in den Speicher des Rechner/Routers

Commen Application Program Interface. Ist eine Schnittstelle
aehnlich Netbios zwischen Anwendungssoftare und dem CAPI-Treiber
im PC. Hatte CAPI von 1990 noch eine Beschreibungsvolumen von
40kByte, so sind es jetzt schom ueber 1MByte. Es gibt ein
Projekt ROLAND, das (gegen Geld) Schulungen und Zertifizierungen

S0 Vier-Draht ISDN Schnittstelle. Wird von der Telecom nur noch als
Western (RJ45) Schnittstelle installiert. Ein Einzelgeraet kann
bis 1km vom NT (Netzabschluss der Telecom) entfernt ueber die
vier Draehte angeschlossen werden, bei Busbetrieb (mehrere
Geraete an der gleichen S0) kann die Ausdehnung max. 150m

Die vorhandene HICOM in der GMD, kann mit Zusatzaufwand auch
S0-faehig gemacht werden. Die von Siemens benutzten Protokolle
sind jedoch mitunter nur muehsam und unter erheblichen Zeitver-
lust auf 1TR6 bzw. Euro-ISDN abbildbar. Die Anlage ist z.Zt.
noch nicht Telecom-seitig ISDN-faehig. Im August 94 soll die
Umstellung der HICOM-Anlage der GMD erfolgen.

Nationales ISDN-Protokoll. Wesentliche Eigenschaften, die es von
Euro-ISDN unterscheidet, sind semipermantente Verbindungen und
das Subadressierungsmodell. Bis zu acht Geraete am S0-Bus
koennen von aussen direkt angewaehlt werden. Sie werden durch
die Endziffer unterschieden (EAZ). Der EAZ 0 und 9 kommt einen
Sonderbedeutung zu.

Verschiedene Rufnummern koennen beim Euro-ISDN einem S0
Anschluss beliebig zugeordnet werden. Anrufweiterleitung und
andere Dienste koennen daher je Rufnummer geschaltet werden. Es
gibt aber auch keinen Global-Ruf. Von der Telecom werden dem
Euro-ISDN-Anschluss drei Rufnummern ohne Zusatzzahlung

Beim PC ist im Bios der Interrupt 14 fuer die Bedienung der
seriellen Schnittstellen vorgesehen. Da dieser aber so schlechte
Funktionalitaet und Performance zur Verfuegeung stellt, gibt es
kaum ein Programm, das hierauf zurueckgreift. In der Regel wird
die Hardware (der serielle Port eines PC ist durch den schon zu
Entwicklungszeiten des PC veralteten 8250 realisiert) direkt vom
Anwendungsprogramm programmiert. Der Fossil-Treiber ist der
Versuch einer Neudefinition des INT14 dieses Bios-Dienstes.
Voraussetzung zur Benutzung ist natuerlich, dass das Anwendungs-
programm diesen nutzt. Bei Kermit ist dies z.B. der Fall.
Vorteil ist immer dann zu erwarten, wenn man hardwareunabhaengig
sein moechte. Durch Auswechseln des Treibers kann dann dasselbe
Programm ueber ein LAN oder ISDN genauso weiterverwendet werden.

Ist ein Fossil-Treiber (s.o.) der auf der CAPI Schnittstelle
aufsetzt. Zusaetzlich emuliert er ein Modem. Die CAPI wird also
ueber entsprechende AT-Befehle und S-Register gesteuert.

Ist ein Packet-Treiber, der auf CAPI aufsetzt. Er kann mit
unterschiedlichen ISDN-Gegenstellen kommunizieren. IP-Pakete
werden je nach Parametrisierung in X75 Pakete, in V110 Streams
mit Byte-Stuffing als auch in HDLC-Frames verpackbar. ISPA kann
auch F3/F5 als auch SLX und SLIP.
siehe FOSSIL

Ist ein Packet-Treiber fuer SLIP und setzt auf der CAPI auf

gehen auf eine Definition von Ftp Inc. zurueck. Die Definition
ist Public Domain. Russ Nelson hat fuer die Packet- Treiber
Implementierung wichtige und vereinfachende Routinen
geschrieben, so dass sich der Schreiber eines neuen Treibers auf
die Software fuer seine Hardware konzentrieren kann. Die Folge
ist, dass die entstandenen Treiber wiederum im Source verfuegbar
sind und verteilt werden. Leider gibt es noch keine Packet-
Treiber fuer ISDN-Karten, die meisten der verfuegbaren Treiber
wurden fuer Ethernet Karten geschrieben.

Treiber haben dieselbe Funktion wie Packet-Treiber; da die
Definition von Novell stammt, sind sie fuer Netware

Treiber haben dieselbe Funktion wie Packet-Treiber; da die
Definition von Microsoft stammt, sind sie fuer den Lan-Manager

definiert die serielle Schnittstelle elektrisch als
differentielle Signale.

definiert die serielle Schnittstelle mit V24 Signalpegeln, auch
fuer die Datenclocks.

Service Indicator
wird im D-Kanal uebertragen, um den Typ des Endgeraetes
anzuzeigen. Telefon, Fax und Modem koennen z.B. so dieselbe
Rufnummer haben, und wissen dann jeweils selbst, wenn sie
gemeint sind. Interessant ist meist der "additional" Service
Indikator, der von den Teilnehmereinrichtungen mitgeschickt
werden kann. Oft sind bei den verschiedenen Herstellern die
Bedeutungen unter- schiedlich. Daher ist es stets sinnvoll, wenn
der Indikator von der Endanwendung parametrisierbar ist.

Ist ein Protokoll oberhalb von X75 (siehe oben). Spielt eine
Rolle in Verbindung mit BTX und Euro-File-Transfer.

Die semipermanente Verbindung ist ein Angebot der Telekom,
aehnlich einer Festverbindung bedarfsgesteuert zu einem vorher
bestimmtem Partner eine Verbindung (zu einem monatlichen
Festpreis) aufzubauen. SPVs setzen einen 1TR6-Anschluss voraus.

__ _____ __ __
| || _ \ | \/ | Jan-Piet Mens Tel: +49-521-9225922
__| || ___/ | | Haendelstrasse 19 Fax: +49-521-9225924
|_____||__| |__||__| D-33604 Bielefeld

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