AppleTalk is a simple networking protocol built in to the Macintosh OS. It is designed to run over LocalTalk, a transport layer based around twisted pair and RS422 serial signalling, supported by every Macintosh ever made. My Macintosh PowerBook Duo has just two ports: a phone connector for the modem, and a serial/localtalk connector. This is why I was motivated to get a working AppleTalk network going here at ICSI.
AppleTalk lets macs talk to Apple printers and other macs (for file sharing) directly. In combination with a bridge, it can also support TCP/IP networking over Ethernet. Happily, ICSI has long owned such a bridge (a Shiva FastPath 5, also known as a 'Kinetics' box, whose network name is "icsi-kin1") so plugging a mac into the ICSI AppleTalk network allows it to access the internet too.
With AppleTalk bridged to the Ethernet, there are a number of packages to provide Macintosh system services from Unix hosts. I've installed the CAP/AUFS package (Columbia Appletalk Protocol/Apple-Unix File System) on YAM.ICSI.BERKELEY.EDU (formerly it ran on MONTOYA). This allows the machines on the AppleTalk network to use Unix disks as file servers (after a little bit of setup - see man AUFS on MONTOYA).
CAP also provides for allowing Macs to print to Unix printers, but with the inclusion of the LPR protocol in the Apple LaserWriter 8.5.1 driver software, this is the better solution, so we don't use CAP for this any more.
We actually run our LocalTalk network over the serial cabling originally installed for dumb terminals. We use the PhoneNet interfaces which purport to allow a daisy-chain (or even a limited star) of network branches up to several thousand feet long over standard telephone wiring. Although there have been a few reliability problems, the current setup seems pretty stable.
This page is to provide some kind of documentation for the wiring involved in this network. Inevitably, it will get out of date. But at the time of creating this page, the network wiring is as shown below.
It's effectively a single daisy chain across both floors, with the "icsi-kin1" bridge located somwhere near the middle. I moved the bridge to my office because it was not reliably available to all nodes when it was in room 631.
1998mar06: Note that since I was able to connect the Power Mac in room 631 directly to EtherNet, I have disconnected the link up to the 6th floor by putting a terminator on the node in room 557. Hopefully, this much shorter daisy chain will be faster and more reliable (as long as we keep both terminating ends plugged in!).