AppleTalk facts for kids

Quick facts for kids
AppleTalk

Protocol stack
Developer(s)	Apple Computer
Introduction	1985; 40 years ago (1985)
Hardware	LocalTalk, others

AppleTalk was a special set of rules, called a protocol suite, that Apple Computer made for their Macintosh computers. It helped these computers connect to each other and share things like printers and files.

What made AppleTalk cool was that it was super easy to set up. You didn't need a special expert or a central computer to make it work. AppleTalk-equipped computers would automatically find each other, get their own addresses, and get ready to share.

Apple released AppleTalk in 1985. It was the main way Apple devices connected in the 1980s and 1990s. You could also find versions for IBM PC computers and the Apple IIGS. Many printers, especially laser printers, also used AppleTalk.

In the 1990s, a different set of rules called TCP/IP became very popular. Because of this, Apple slowly stopped using AppleTalk. By 2009, with the release of Mac OS X v10.6, AppleTalk was no longer supported. Many of AppleTalk's easy setup features later appeared in a newer Apple technology called Bonjour.

How AppleTalk Started

Early Ideas: AppleNet and AppleBus

After the Apple Lisa computer came out in 1983, Apple wanted to create a way for computers to connect in a local area network (LAN). They called this idea AppleNet. It was based on a system from Xerox, but Apple used its own special cables. AppleNet was announced in 1983, but it was later canceled.

Around the same time, Apple was working on the Macintosh computer. Engineers decided to use a special chip called the Zilog 8530 serial controller (SCC). This chip was more expensive but allowed faster connections and fewer ports on the computer. The first idea for this was called AppleBus. It imagined the Macintosh controlling simpler devices connected to it.

Making Networking Easy

The Macintosh team was also developing the LaserWriter printer. They needed a way for many people to share this expensive printer. By late 1983, it was clear that another networking system, IBM's Token Ring, wouldn't be ready in time for the Mac's launch.

So, Apple decided to create a new networking system based on the AppleBus hardware. This new system was designed to be super easy to use, just like the Mac itself. You could plug it in, and it would just work, without needing special setup or fixed network addresses. This was a big deal for the time!

In early 1984, the "new" AppleBus was announced. It allowed Macs and Lisas to connect directly using a small box plugged into the serial port.

AppleTalk Personal Network is Born

Just before it was released in early 1985, AppleBus was renamed AppleTalk. At first, it was called AppleTalk Personal Network. It included a family of network rules and the physical way they connected.

The first physical connection, later called LocalTalk, had some limits. It was not very fast (230.4 kilobits per second), could only go about 1,000 feet, and connect up to 32 devices. But since the basic parts were built into the Mac, adding devices was cheap, costing about $50 for an adapter box. Other networking cards at the time cost hundreds or thousands of dollars.

AppleTalk was designed to be expanded later. It could handle up to 255 devices on a network. You could also connect different AppleTalk networks using "bridges" (which are like early routers). These connected networks could be organized into "zones" to make them easier to manage.

The best part of AppleTalk was how easy it was to use. To join a device, you just plugged in the adapter and connected a cable. The AppleTalk system would automatically get a network address, give the computer a name you could understand, and show you a list of other devices on the network. This made it simple to find printers or file servers using a program called the Chooser. AppleTalk was so simple that people often created small networks just by plugging Macs together in the same room!

PhoneNet and Other Adapters

Over the next few years, many companies made their own AppleTalk devices. One popular one was PhoneNET from Farallon. This adapter let AppleTalk networks use regular phone wires, which were very cheap. You could even use the same phone cable for both your phone and your AppleTalk network!

Other companies made adapters that allowed AppleTalk to run faster, up to 1 megabit per second. These often used special clocks to speed up the connections.

AppleTalk on Faster Networks

As Apple started selling more computers to businesses and schools, they needed AppleTalk to work with existing, faster networks like Ethernet. So, Apple created EtherTalk 1.0 in 1987. This allowed AppleTalk to run over Ethernet cables. It was introduced with the Macintosh II, one of the first Macs with expansion slots.

With EtherTalk, users could choose which connection to use for networking. Ethernet cards were available from companies like 3Com. The new system also allowed up to 255 devices on a network. When EtherTalk came out, AppleTalk Personal Network was renamed LocalTalk to show it was the slower, built-in option. Later, a similar product called TokenTalk supported Token Ring networks.

By 1987, AppleTalk was very popular, with more installations than any other networking system in the world.

That same year, Apple also introduced AppleShare. This was a special program that turned any Mac with enough memory into a file server. It allowed people to share files easily across the network.

AppleTalk Phase II and Beyond

In 1989, a major update called AppleTalk Phase II was released. This version made AppleTalk more flexible. Networks could now have more than 255 devices, and "zones" (groups of devices) were no longer tied to physical networks. This meant you could create a "Printers" zone that listed all printers in a company, no matter where they were physically located. Phase II also made the network less "chatty," which helped when connecting networks over long distances.

By 1990, Ethernet was becoming very common. Apple started building Ethernet ports directly into Macs. They used a special connector called AAUI (Apple AUI) that allowed users to plug in adapters for different types of Ethernet cables.

Later, as a type of Ethernet called 10BASE-T became standard, newer Macs like the Power Macintosh started including 10BASE-T ports directly. Eventually, AAUI was phased out, and 10BASE-T became the standard Ethernet connection on Macs.

The Internet Arrives

From the beginning, people wanted to connect Macs using AppleTalk to the TCP/IP networks that formed the early internet. In 1984, a project at Stanford University allowed IP data to travel over AppleTalk networks. Later, Apple released MacTCP in 1988, which allowed Macs with Ethernet to use TCP/IP.

In the early 1990s, Macs were very important for connecting to the growing Internet. Programs like Fetch (for file transfer) and NCSA Mosaic (an early web browser) were widely used on Macs.

As the world moved to IP for all networking, Apple had to update its systems. They created Open Transport, a new way to handle both MacTCP and AppleTalk. However, early versions had some problems.

What Happened to AppleTalk?

When Apple bought NeXT and started developing Mac OS X, AppleTalk became an older system. Mac OS X still supported AppleTalk so people could use their existing printers and file shares. But as new technologies like USB for printers became popular, AppleTalk was used less and less. Apple finally removed AppleTalk support from macOS in Mac OS X v10.6 in 2009.

Even though AppleTalk is gone, its idea of easy-to-use networking lives on. Apple has created new technologies like AirPort (for Wi-Fi) and Bonjour (for finding devices automatically) that offer similar ease of use, but now using modern IP networks.

As of 2020, AppleTalk is completely removed from macOS 11 Big Sur.

How AppleTalk Worked

AppleTalk was designed in layers, much like the OSI model that describes how networks communicate.

One special thing about AppleTalk was that it had two protocols that made it automatically set itself up. The AppleTalk Address Resolution Protocol (AARP) helped devices get their own network addresses. The Name Binding Protocol (NBP) was a dynamic system that connected network addresses to names that people could easily read. This meant you didn't have to remember complicated numbers for devices.

Both AARP and NBP allowed special devices, like routers, to control the addresses and names on larger networks. This helped reduce "chattiness" when new devices joined. Together, AARP and NBP made AppleTalk a very easy-to-use network. You just plugged in a new machine, and it would find its place on the network. The Chooser program would then show you a list of available devices, like file servers and printers.

Addressing Devices

An AppleTalk address had four parts: a network number, a device number (node number), and a socket number. Only the network number usually came from a router. Each device chose its own device number automatically, making sure no two devices had the same one.

Because addresses were chosen automatically, users couldn't just type in an address to find a service. Instead, all services had names that people chose, like "My Printer" or "Shared Files." These names were easy to remember and could be long enough to avoid confusion.

An NBP name pointed directly to a service on a machine, not just the machine itself. This meant if a service moved to a different computer, it could keep the same name, and users wouldn't notice any change. Also, one computer could offer many different services without any network problems. This is different from how many modern internet systems work, where a name usually points to a computer's address, not a specific service.

Key AppleTalk Protocols

AppleTalk Address Resolution Protocol (AARP)

AARP helped AppleTalk devices find each other's physical addresses on the network. When an AppleTalk machine turned on, it would ask for a network address. If no router gave it one, it would pick a random address and announce it. If another device already had that address, the new machine would pick another until it found a free one. To speed things up, the successful address was saved for next time.

AppleTalk Data Stream Protocol (ADSP)

ADSP was added later to AppleTalk. It was like TCP on the internet, providing a reliable way to send data. It had some differences from TCP, like allowing connection attempts to be rejected and having a special "attention message" system for urgent, short messages.

Apple Filing Protocol (AFP)

The Apple Filing Protocol (AFP) is the set of rules for talking to AppleShare file servers. It helps users log in and lets them work with files on the server, similar to how files are organized on a Mac. AFP is still used in macOS today, even though most other AppleTalk protocols are no longer used.

AppleTalk Session Protocol (ASP)

ASP was a middle-layer protocol that helped with requesting responses to commands and checking the status of devices. It also allowed servers to send special "attention" messages to clients.

AppleTalk Transaction Protocol (ATP)

ATP was the first reliable way to send data in AppleTalk. It was a simple request-and-response system. When one device sent a request, it could get up to eight response packets back. The sender would then confirm which packets it received, and the other device would resend any missing ones. ATP could make sure operations happened "exactly once," which was important for things like saving files.

Datagram Delivery Protocol (DDP)

DDP was the lowest-level transport protocol. It sent data packets without guaranteeing they would arrive. All other AppleTalk protocols, like NBP and RTMP, were built on top of DDP. DDP is similar to the Network layer in the OSI communication model.

Name Binding Protocol (NBP)

NBP was a dynamic system for managing AppleTalk names. When a service started, it registered a name chosen by a person. NBP made sure no other device had the same name. When a user wanted to find a service, NBP helped them search for it by name. NBP allowed users to browse for services (like "what printers are available?") and find specific ones. Names could include spaces and different letter cases.

AppleTalk Echo Protocol (AEP)

AEP was a protocol used to test if a network device could be reached. It sent a packet to a device, and if the device received it, it would send a copy back. This was a simple way to check if a connection was working.

Printer Access Protocol (PAP)

PAP was the standard way to talk to PostScript printers. It was built on top of ATP. When a print job started, the computer would send parts of the print code, and the printer would send back any messages. This system also allowed other Macs on the network to check the printer's status, even if it was busy printing.

Routing Table Maintenance Protocol (RTMP)

RTMP was how AppleTalk routers shared information about the network's layout. Every 10 seconds, routers would send out a list of all the network numbers they knew about and how far away they were.

Zone Information Protocol (ZIP)

ZIP connected AppleTalk network numbers with zone names. A zone was a way to group parts of the network that made sense to people, like "Accounting Department." A zone could include different parts of the network that weren't physically connected.

How AppleTalk Was Built

Inside an Apple LocalTalk adapter box. These boxes cost about $90 in 1989. They automatically stopped the signal at the end of the network cable.

Farallon PhoneNET adapter

The first way AppleTalk connected was called LocalTalk. It used the Mac's built-in serial ports at 230.4 kilobits per second. LocalTalk used a splitter box to connect cables from one computer to the next, like a chain. It was slow compared to today's networks, but at the time, it was much easier and cheaper than other options for personal computers.

A very popular replacement for LocalTalk was PhoneNET from Farallon. It also used the Mac's serial port but ran over very cheap, standard phone cables. You could even use existing phone jacks! PhoneNet was popular because it was cheap, flexible, and easy to fix if there was a problem.

AppleTalk protocols also worked over Ethernet (called EtherTalk) and Token Ring (called TokenTalk). EtherTalk became the most common way to use AppleTalk as Ethernet became popular in the 1990s. Ethernet networks could also carry other protocols at the same time, like TCP/IP.

Networking Layers

AppleTalk followed a layered model, similar to the OSI model, to organize its different protocols:

Versions of AppleTalk

AppleTalk had several versions over the years, often updated with new Mac OS releases.

Connecting with Other Computers

When AppleTalk first came out, most office computers were PCs running MS-DOS. Apple made an AppleTalk PC Card in 1987 so PCs could join AppleTalk networks and print to LaserWriter printers. Later, AppleShare PC allowed PCs to access AppleShare file servers.

Other companies also created ways for PCs to use AppleTalk. For example, the "TOPS Teleconnector" system allowed MS-DOS PCs to share files and printers over AppleTalk networks.

Today, operating systems like BSD and Linux can still support AppleTalk through an open-source project called Netatalk. This allows them to act as file or print servers for older Macintosh computers.

Microsoft Windows Server operating systems also supported AppleTalk for a while, starting with Windows NT and ending after Windows Server 2003. Some companies still offer special software to help Windows servers work with older Mac AppleTalk systems.

See Also

In Spanish: AppleTalk para niños

• Netatalk is a free, open-source implementation of the AppleTalk suite of protocols.
• Network File System
• Remote File Sharing
• Samba
• Server Message Block