Wi-Fi for my Powerbook 520

A simple Wi-Fi upgrade:

You will need:

  • A Linux laptop/netbook with a Wi-Fi connection.
  • A special serial cable (round mini-din to 9 pin).
  • A USB to RS232 converter cable (unless your Linux machine has a real serial port).

I know that using a perfectly good laptop in this way could be considered cheating, but considering the cost of a low end machine that has Wi-Fi and the fact that a really low spec. Linux install would suffice I think it is worth considering.

Linux has for a very long time supported a PPP connection, we will take advantage of this to connect the vintage Mac.  You will need the MacPPP extension and control panel installed, and I am assuming that you are using MacTCP too.  I haven’t tried MacPPP with Open Transport so I don’t know if it would work.

First of all verify that we have pppd installed on our Linux machine, you will need a root shell:

whereis pppd

normally it is in /usr/sbin, assuming it is create a new file in /usr/sbin called pppd.init:



# ensure pppd is always running

tasks=`ps ax|egrep "[p]ppd"|grep -v "pppd.init"|wc -l`

if [ $tasks -eq 0 ]; then
/usr/sbin/pppd /dev/ttyUSB0 19200 ktune nocrtcts proxyarp passive local


(apologies for the small font above, but it was to make sure the pppd line stays intact)

You will need to change the to your Linux machines IP address, and the to a free IP address on your network.  You may need to change the ttyUSB0 if your adapter has a different device name or if you have a real serial port.  Make this file executable with a chmod +x, but don’t run it yet.

now we need to edit /etc/ppp/options

There are lots of commented out and empty lines in this file making it difficult to see at a glance the settings.  Still as root run the following:

cat /etc/ppp/options |grep -v "^#"|grep -v "^$"

This basically cuts to the chase and shows you what options are set.  My options file is below:


asyncmap 0
lcp-echo-interval 10
lcp-echo-failure 4


You will need a special cable to convert the Macintosh’s round serial port to a more convenient 9 pin Male.

RS422 Cable

Then you can use a standard 9 pin to 9 pin ‘Null modem’ cable.

Connect the cables together and then from the Mac to the serial port on the USB adapter (or direct if you have a real serial port).  On the Mac open up the ‘Config PPP’ control panel.

Create a new connection, I called mine N150 after the model of the Netbook I am using.

Copy my configuration below:

PPP Config

Execute pppd.init on the Laptop/Netbook, and then click open in the ‘Config PPP’ control panel.  If PPP shows as UP then well done and onto the next step.


With PPP up, go to the MacTCP control Panel.


Select PPP if it isn’t already and then click More…


You need to make sure that your Gateway and DNS settings are correct here for your network.

You will notice that after a disconnect, you wont be able to re-connect, this is because pppd is no longer running.  You can fix this by simply re-executing pppd.init on the Linux machine.  When you are happy simply place pppd.init into a cron script that runs every minute and you can then forget about it.

This system will also work with conventionally cabled Linux PC’s and most Vintage Macintosh computers right down to the 68000 machines like the Macintosh Classic.


If you use my settings and scripts above there will be debug info in the Linux system’s main log.  Either /var/log/syslog or /var/log/messages.


This entry was posted in Vintage and Retro Computing and tagged , by Sean. Bookmark the permalink.

About Sean

A self motivated highly experienced software developer and IT professional. Extremely technical, thorough and with excellent problem solving skills. Able to develop on a wide variety of systems and integrate heterogeneous platforms together. A proven track record of project successes from conception through to delivery. In depth knowledge acquired through exposure to a wide variety of technologies.

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