To configure your modem, you can alter the initstring of your modem. To learn more about your modem, check Ask Mr. Modem.

Now, you need to have the ppp-package installed (check this by typing pppd --version), make sure you have a recent one. Then you have to make sure you've got these files:

/usr/local/bin/ppp

	#!/bin/sh

	case $1 in
		(on|start)
			TELEPHONE='555-1212'        # The telephone number for the connection
			ACCOUNT='your_login'        # The account name for logon (as in 'George Burns')
				PASSWORD='your_pass'        # The password for this account (and 'Gracie Allen')
			INITSTRING='AT&F&C1&D2Z'# Modem initstring
			IPLOCAL=0.0.0.0             # Local IP address if known. Dynamic = 0.0.0.0
			IPREMOTE=0.0.0.0            # Remote IP address if desired. Normally 0.0.0.0
			DEVICE=/dev/ttyS1           # Serial Device com1=ttyS0, com2=ttyS1,...
			SPEED=57600                 # 19200, 38400 or 57600 (don't try something different)
			export TELEPHONE ACCOUNT PASSWORD INITSTRING
			exec /usr/sbin/pppd $DEVICE $SPEED $IPLOCAL:$IPREMOTE \
			user $ACCOUNT connect /etc/ppp/ppp-on-dialer
			;;
		(off|stop)
			if [ -r /var/run/ppp0.pid ]; then
				kill -INT `cat /var/run/ppp0.pid`
				if [ ! "$?" = "0" ]; then
					rm -f /var/run/ppp0.pid
					echo "ERROR: Removed stale pid file"
					exit 1
				fi
				exit 0
			fi
			echo "ERROR: PPP link is not active on ppp0"
			exit 1
			;;
		(info|status)
			/usr/sbin/pppstats
			;;
		(*)
			echo "Usage: ppp on|off|info|start|stop|status";
	esac

/etc/ppp/ppp-on-dialer

	#!/bin/sh

	exec /usr/sbin/chat -v                                        \
		REPORT CONNECTION                                     \
		REPORT CARRIER                                        \
		TIMEOUT              10                               \
		ABORT                '\nBUSY\r'                       \
		ABORT                '\nNO ANSWER\r'                  \
		ABORT                '\nNO CARRIER\r'                 \
		ABORT                '\nNO DIALTONE\r'                \
		ABORT                '\nRINGING\r\n\r\nRINGING\r'     \
		ABORT                'Invalid Login'                  \
		ABORT                'Login incorrect'                \
		''                   "\r$INITSTRING\r"                \
		'OK-+++\c-OK'        'ATH0'                           \
		TIMEOUT              45                               \
		OK                   "ATDT$TELEPHONE"                 \
		CONNECT              '\d\c'                           \
		ogin:--ogin:         "$ACCOUNT"                       \
		ord:                 "$PASSWORD"

You can remove the -v once everything looks normal.

The pppd command uses /etc/ppp/options to list its options, change these options to whatever fits. These defaults normally work in most cases.

	asyncmap 20a0000
	crtscts
	debug
	default-mru
	defaultroute
	detach
	escape 11,13,ff
	hide-password
	ipcp-accept-local
	ipcp-accept-remote
	lcp-echo-failure 4 
	lcp-echo-interval 400 
	lock
	modem
	mtu 1500
	netmask 255.255.255.0
	noipdefault
	passive

	#idle 300 
	#kdebug 0
	#-vj

Once dialing in works like a charm, you can leave debug out.

If your ISP requires CHAP or PAP, you need one of these files with their proper username and password:

/etc/ppp/pap-secrets or /etc/ppp/chap-secrets

	#client         server  secret          IP      
	your_login      *       your_pass       *

To configure your nameservers, change /etc/resolv.conf. If dialing in is succesful, but you can't get it to connect to URL's: this is probably the cause.

	domain domain_of_your_isp
	nameserver your_primary_nameserver
	nameserver your_secondary_nameserver

Before you can run a (shell)script, it must be set executable. Be sure that you set the permissions so that other users cannot see the passwords stored in the files. If you want other users to be able to dial in, you might want to consider using sudo. You might want to do the following:

	chmod u+rw og-rwx -R /etc/ppp
	chmod u+x /etc/ppp/ppp-on-dialer /usr/local/bin/ppp

Then if /usr/local/bin is in your PATH, you can easily dial in with ppp on, hangup with ppp off and to get some statistics, you do: ppp status.

If you're using a 2.2 kernel, it's recommended to get an updated version of the ISDN code. You can retrieve it from CVS at ftp://ftp.suse.com/pub/isdn4linux/. For more information, check: http://www.brisse.dk/site/linux/docs/isdn.htm

Once the ISDN is in place, you can start up the driver. Eg: modprobe hisax type=11 protocol=2 Refer to the Readme's for the right parameters and values for your card.

Next, you'll need the ISDN4Linux toolkit. You can retrieve the latest version of the toolkit at: ftp://ftp.suse.com/pub/isdn4linux/

With the tools installed and configured, write a script to configure the interface, to be used for the ISDN connection. As always in Linux, there's no one correct way of doing this. I've put these in a script

/etc/rc.d/rc.isdn:

	#!/bin/sh

	MSNREMOTE='555-1212'    # Phone number of ISP
	MSNLOCAL='555-1313'     # my number, without 0, with areacode
	ACCOUNT='george'        # The account for logon (as 'George Burns')
	IPLOCAL=10.0.0.2        # my fixed IP (use 10.0.0.2 if no fixed)
	IPREMOTE=0.0.0.0        # IP number of ISP
	INTERFACE=ippp0
	/sbin/modprobe hisax type=11 protocol=2
	/sbin/isdnctrl verbose 3 system on
	/sbin/isdnctrl addif $IF
	/sbin/isdnctrl secure $IF on 
	/sbin/isdnctrl addphone $IF out $MSNREMOTE
	/sbin/isdnctrl eaz $IF $MSNLOCAL
	/sbin/isdnctrl huptimeout $IF 300
	/sbin/isdnctrl l2_prot $IF hdlc
	/sbin/isdnctrl l3_prot $IF trans
	/sbin/isdnctrl encap $IF syncppp
	/sbin/isdnctrl dialmode $IF auto
	/sbin/ifconfig $IF $IPLOCAL pointopoint $IPREMOTE -arp -broadcast
	/sbin/ipppd /dev/ippp0 user $ACCOUNT $IPLOCAL:$IPREMOTE

To start this at boot time, make it executable and append the following to /etc/rc.d/rc.local:

	if [ -x /etc/rc.d/rc.isdn ]; then
		. /etc/rc.d/rc.isdn
	fi

The ipppd command gets its parameters passed through a file, /etc/ppp/ioptions:

	-ac
	-bsdcomp
	debug
	defaultroute
	ipcp-accept-local
	ipcp-accept-remote
	mru 1524
	mtu 1500
	noipdefault
	-pc
	useifip
	-vj
	-vjccomp

	#idle 360
	#persistent

Finally, create /etc/ppp/ip-down.local to handle the shutdown of the interface:

	#!/bin/sh

	/sbin/ifconfig $1 down
	sleep 1
	/sbin/ifconfig $1 10.0.0.2 pointopoint 

If your ISP uses PAP or CHAP, create a file /etc/ppp/pap-secrets or /etc/ppp/chap-secrets. Its format is:

	#client         server  secret          IP      
	your_login      *       your_pass       *

Not really related to ISDN, but a lot of people forget this step (too eager to try out all the stuff they typed in above ? :-)).

Anyway, you need to configure the DNS, by creating a file /etc/resolv.conf:

	domain your_domain_of_your_isp
	nameserver your_primary_nameserver
	nameserver your_secondary_nameserver

Before you can run a (shell)script, it must be set executable. Be sure that you set the permissions so that other users cannot see the passwords stored in the files. If you want other users to be able to dial in, you might want to consider using sudo. You might want to do the following:

	chmod u+rw og-rwx -r /etc/ppp
	chmod u+x /etc/rc.d/rc.isdn /etc/ppp/ip.down-local /usr/local/bin/isdn

Finally, you can write a little wrapper to start and stop the ISDN connection. I've put this as /usr/local/bin/isdn:

	#!/bin/bash
	
	case $1 in
		(on|start)
			/sbin/isdnctrl dial ippp0
			;;
		(off|stop)
			/sbin/isdnctrl hangup ippp0
			;;
		(info|status)
			/sbin/isdnctrl list ippp0
			;;
		(*)
			echo "Usage: isdn on|off|info|start|stop|status"
	esac

Then if /usr/local/bin is in your PATH, you can easily dial in with isdn on and hangup with isdn off.