DirectLink 1.0

Was motivated by a small omission from the Prefs panel for setting up a PPP conection
directly through a serial cable without a modem, which for development of network apps
will come in very handy since you don't need to be on the phone all day. I have recently 
learned that the magic phone number 00 will do the trick, but that you are limited to 19200bps.
DirectLink will allow you to select baudrate upto 57600.

I have tested the program with Linux Redhat 4.1. Windows NT RAS should work as well.

You can probably get away without having chat scripts, but I think it's nicer to have one
than always having to start pppd manually on the Linux box.

Here is what you need to setup on Linux to use a chat script:

1. Make sure you have the getty program on your system, my Redhat 4.1 didn't have it
and I had to download the package and install it.

2. Add the getty to your /etc/inittab, typical entry:

	7:2345:respawn:/sbin/getty ttyS0 DT38400    #change according to your port and speed
						    #ttyS0 == Com1 ttyS1== Com2
 		
3. If you want to use 57600bps, you need to have your serial port set to spd_hi
with the following command (you probably want to add it to your /etc/rc.d/rc.local ) 

	set_serial /dev/ttyS0 spd_hi
	
This will cause the baudrate request of DT38400 to be translated to 57600.

4. Run "init q" command and check that getty is running either by "ps aux" and/or by
using  terminal program like PalmTerm to login to the box as some user. Of course you need 
to have a pilot modem cable with a null modem adapter and an additional modem cable to extend 
the reach, unless you like spending time under your desk. Or,  I think the cradle can be
used instead, though I haven't tried it.

5. Once you can login on the serial port, it would make things easier if you add an
alias for the pppd command to the user's .bashrc or .profile, depending on the shell:

	alias ppp="exec /usr/sbin/pppd -detach debug"

6. Your /etc/ppp/options should have:
	lock
	crtcts

7. Your /etc/ppp/options.ttyS0  (change the file name according to the tty you are using)
contains options specific to the port. This is where I assign the IP addresses for the link.
You can do it differently, and set them on the pilot, I haven't tried it. So the file
contains (change them to the desired ip addresses) :

#linuxaddress:pilotaddress
192.168.1.1:192.168.1.2


Pilot Setup:

1. In Prefs/Network, make a duplicate of the Unix Service. enter any appropriate
information like the user and password and any additional . If you did step 7 above, then
check the box for auto IP adresses. No need to bother with modem stuff.

2. Change the chat script to be:

send cr:
send cr:
wait for:ogin:
send User ID:
send cr:
wait for: word:
send Password:
send cr:
wait for:$               (or whatever your shell prompt is )
send: ppp                (this is the alias for the the ppp command which starts pppd)
send cr:


Running DirectLink

1. DirectLink always connects with the last used Service.  Make sure that you try to connect using this Unix copy
Service from the Prefs app to set the Service to be used by DirectLink.
This will fail since you did not set up a a phonenumber or modem, but is required for running
DirectLink. After another service is used to make a connection, you have to retry
connecting with the Unix copy service before running DirectLink.
2. To disconnect the connection, use the Prefs App disconnect button.


Troubleshooting

If you run into problems, look in the /var/log/messages or /usr/adm/messages or wherever 
your system syslogs.  You should see messages about the fact that the user has logged in
and messages from the pppd starting and negotiating ip address. This should clue you in
on what's going on.  

If you know you your getty is working, because you verified it with PalmTerm, and the 
connection fails, but you don't see any messages in your log files, then a problem with
the chat script is a good possibility for the source of the problem.

Good luck,

Metasync Inc.
info@metasync.com
http://www.metasync.com