Author: Ian Barry, email: ian (at) northlodge (dot) org Date: June 2001
This document aims to cover some of the experiences involved in setting up Linux for IrDA communication with today's IrDA-complaint handheld devices. This work is taken from some personal experience whilst conceptually working on unspecified IrDA extensions to static, web-enabled office signage designed by Appliance Studio Ltd. and distributed by Steelcase.
This document's emphasis is on setting up network connections between handheld devices and Linux. There are several methods to accomplish this goal - the one covered in this document is the setting-up of a TCP/IP network connection with a PPP (Point to Point Protocol) connection over IrCOMM (serial emulation) over IrDA.
It is assumed that readers of this document are familiar with the Linux's standard IrDA setup as defined in the Linux IrDA HOWTO which can be found at http://www.mobilix.org/Infrared-HOWTO/Infrared-HOWTO.html. If you haven't read this document, read it first!
If people have further experiences, amendments or the like, please contact me and we'll sort it out!
At time of writing, the latest kernel was 2.4.5-ac16. I recommend that readers follow the latest kernel in the Alan Cox (ac) branch as these seem (in my experience) to contain the latest IrDA patches. Alan's kernel patches can be found in /pub/linux/kernel/people/alan/2.4/ of your local kernel mirror (e.g.
ftp.uk.kernel.org).
PPP
Setting up of the PPP daemon is a little bit of an art. This section just adds my experiences to those found in the Linux IrDA HOWTO. So if you have not read that yet - do it now otherwise you probably won't understand what I am on about.
I use the following options for PPP. These options should be found in a file in /etc/ppp/peers/. It can have any filename but for simplicity I chose /etc/ppp/peers/ircomm. Note: The file /etc/ppp/options should just contain the word lock and nothing else.
/dev/ircomm0 115200 noauth modem debug detach connect "/etc/ppp/mychat" asyncmap 0xa0000 passive nocrtscts nocdtrcts
I use a custom connect script because I can debug it better. A custom script is not compulsory but I found it quite useful for hacking around. I also wanted to write a PPP script that could cope with connections from differing devices without restarting. This script will handle direct connections from incoming handhelds. It will also emulate a modem for those handhelds that only support the "irda modem" connection option.
The script is in C and can be found here. It should be compiled with gcc -O2 -o mychat mychat.c. The resulting binary should be put in /etc/ppp/ (or wherever was specified in the connect option in the PPP options file above). This script should work with the devices mentioned in this document.
The PPP daemon can be started once-off with the following command. It is assumed that the Linux box has an interface 192.168.0.2/16 and a DNS server of 192.168.0.1. Replace ircomm with the name of the PPP options file above. (A script that I wrote to run this daemon continually can be found here.)
/usr/sbin/pppd call ircomm 192.168.0.2:192.168.55.100 ms-dns 192.168.0.1
Two methods for Palm IrDA connection are examined. The Direct IrDA connection is
simpler and faster than the IrDA Modem Connection. Both configurations
are detailed below, but should already be correctly configured as default on
a new Palm. These instructions are written for the Palm Vx OS 3.5.2 but should be
easily applicable to other versions.
Palm Vx Method 1 - Direct IrDA Connection
| Mode | IR (IrCOMM) to PC/Handheld
| Flow control | Automatic
| Speed | 115,200 bps
| |
| Username (ignored) | blank | ||||||
| Password (ignored) | blank (i.e. prompt) | ||||||
| Connection | IR to PC/Handheld (see (1)) | ||||||
| Connection type | PPP
| Query DNS | checked
| IP Address: Automatic | checked
| Script | none
| |
| Mode | IR (IrCOMM) to Modem
| Dialing | Touchtone
| Flow control | Automatic
| Speed | 115,200 bps
| Init string | none
| |
| Username (ignored) | blank | ||||||||
| Password (ignored) | blank (i.e. prompt) | ||||||||
| Connection | IR to Modem (see (1)) | ||||||||
| Phone # (ignored) | 0
| Connection type | PPP
| Query DNS | checked
| IP Address: Automatic | checked
| Script | none
| |
| Baud | 115200
| Connect via | Infrared
| Fax class | Auto
| Init string | ATZ
| Data/Fax init string | none
| Flow control | Hardware
| Terminal detect | unchecked
| Carrier detect | unchecked
| |
| Service connection | direct
| Manual login | unchecked
| Username (ignored) | me
| Password (ignored) | none
| Get IP address from server | checked
| Get DNS address from server | checked
| Use login script | unchecked
| Enable PPP extensions | checked
| Allow plain text authentication | checked
| Use call back | unchecked
| |
This implementation is very buggy. It will not work at least 90% of the time. This is mainly due to a bad IrDA implementation in WinCE and a non standards- compliant implementation of PPP on WinCE. (As far as I know).
[HKEY_LOCAL_MACHINE\ExtModems] [HKEY_LOCAK_MACHINE\ExtModems\IR] "Port"="COM3:" "DeviceType"=dword:00000001 "FriendlyName"="IR Connection on COM3:"
| Dial-Up Connection: | |||||||||||||||||||||||||||||||||||||||
| Modem | IR Connection on COM3:
| Device Properties: Port Settings:
| Manual Dial | unchecked
| Use terminal window before/after dialing | unchecked
| Baud Rate | 115200
| Data Bits | 8
| Parity | None
| Stop Bits: | 1
| Flow Control | ?? doesn't seem to matter ??
| Device Properties: Call Options:
| Cancel the call if not connected | unchecked
| Wait for dial tone before dialing | unchecked
| Extra Settings | none
| TCP/IP Settings: General:
| Use Server-assigned IP address | checked
| Use Slip | unchecked
| Use software compression | checked
| Use UP header compression | checked
| TCP/IP Settings: Name Servers:
| Use Server-assigned addresses | checked
| | ||||