Apple Announces the AppleTalk Personal Network

Cupertino, Calif., January 23, 1985--Apple Computer, Inc. today introduced AppleTalk*, the low-cost personal network for The Macintosh* Office computers and related peripherals.  The AppleTalk Personal Network lets personal computers share high-performance peripherals and connects computers within a work area of approximately 1,000 feet for a suggested retail price of only $50 per connection, a fraction of current networking costs.  AppleTalk can also serve as a tributary system, using bridges and gateways to link to other networks.

"With AppleTalk, we hope to do for networks what personal computers did for computing--bring the services easily and affordably to a great many people, " said Barbara Koalkin, Macintosh Office products marketing manager.  "We have developed a general-purpose personal network that is easy to install and easy to use while being powerful, fast and truly revolutionary in price.  We want the third-party developer community to have free rein with AppleTalk to design products that add value to the network."

A single AppleTalk network connects up to 32 devices, with the computers and peripherals configured in any combination.  Personal-computer users can share peripherals such as file servers and Apple's new LaserWriter printer. Apple also designed AppleTalk to interact with other networks.  Through intelligent bridges, users will be able to connect two or more AppleTalk networks to form larger networks.  AppleTalk networks will also be able to communicate with other networks through intelligent gateways.  Using AppleTalk Personal Networks as tributary systems in these ways, work groups can exchange information with other groups and with larger computer networks.

"In offices, people spend most of their time working closely with about five to 25 other people, doing related or common projects," Koalkin said. "Until today, networks for these offices have been complicated to install, hard to use and expensive, all of which have limited the number of personal computers currently on networks to less than five percent.  The AppleTalk design has been optimized to be a work-group networking solution that is extremely easy to install and use, thus making it more attractive to work groups in businesses of all sizes."

Developing Products for AppleTalk

More than 50 companies already have products under development for the AppleTalk Personal Network.  Among the new products are hardware devices that connect Apple computers with IBM Personal Computers, an AppleTalk interface to the Ethernet local-area network, gateways to IBM networks, a Unix file server, hard-disk servers and others.

"We have been creating an Ethernet-based, multivendor environment for personal computers since 1982," said Bob Metcalfe, chairman of 3Com Corp., which has developed an Ethernet interface for AppleTalk.  "By opening up AppleTalk to developers, Apple is allowing us to extend this environment to include The Macintosh Office."

Apple has published all protocols for AppleTalk.  The architecture is layered, and it is "open"--as opposed to proprietary--at every layer. Developers and users can gain access to the network as well as add their own protocols at any layer.  Apple expects that publishing complete protocols in this way will spur developers to provide innovative products for AppleTalk.

In addition to positive response from developers, Apple has also received strong support and acceptance for AppleTalk from members of the Apple University Consortium.  For example, beginning last October, 1,200 Macintosh computers were put on a number of AppleTalk networks at Dartmouth College.  The networks, located in student dormitories and campus buildings, are being used for terminal emulation for access to the college's mainframe computers and for document and file transfer between Macintosh computers.

Shared Peripherals will have AppleTalk Built In

Apple's LaserWriter already has AppleTalk built in, as will all future Apple peripherals for the network, including the file server to be introduced later in 1985.

"Including the network as an integral part of the design of the peripherals reduces the cost and complexity for end users, who don't have to add cards to their equipment to let them work on the network," Koalkin said.

Apple also expects that third-party developers will start building AppleTalk into their hardware products because of advantages in cost and ease of development.

Open Architecture Stresses Simplicity, Power and Versatility

Apple designed the AppleTalk Personal Network with a specific goal in mind: to provide work groups with a network that is low-cost and easy to install and use, yet powerful enough for building a broad range of network services for work groups.

Because the circuits to support AppleTalk were built into the Macintosh family of products at the outset, users do not have to open their machines to add cards to connect to AppleTalk.  The AppleTalk Connector Kit consists of a connection  box and cables to link a device to the network, and installation takes only a  few minutes.   Unlike existing networks, AppleTalk needs no network  administrator to install or configure it.

Apple's software design conserves the network's data bandwidth so that data can be transferred at speeds comparable to those of networks with much higher bandwidths. Apple was able to maximize the use of the network's bandwidth of 230.4 kilobits per second by designing very efficient software protocols.  Six kilobytes of software (for the Macintosh)--as compared to dozens of kilobytes for most other networks--are needed to implement the basic network protocols. Small software size also helps speed information transfer through the network.

Much of the AppleTalk architecture is already built into Macintosh and will be built into all the peripherals designed for the network.  With greater intelligence inside the computers and peripherals and outside of the cable, fewer bits are required to transmit information along AppleTalk cables. Thus, the power of the computer and peripherals reduces the network load.

Controlling Traffic Along AppleTalk

The devices connected to an AppleTalk Personal Network exchange data over a shared, shielded, twisted-pair cable.  AppleTalk controls traffic using a software protocol called carrier-sense, multiple access with collision avoidance (CSMA/CA), which was designed to allow all devices to compete equally for access to the cable.

With CSMA/CA, a computer or peripheral device that has data to transmit along the network first "tests the water" by "sensing" whether the line is busy or free.  If other traffic is already on the bus, the computer or peripheral device waits until the line is free before transmitting.

To avoid collision, the devices connected to AppleTalk follow a special collision-avoidance routine.  Upon sensing that the line is free, a network device waits 400 microseconds plus an additional time, determined randomly by the software, before reserving the line via a quick "handshake process."  This process keeps other devices from using the line at the same time.  Other devices seeking access to the cable must continue to test the line until it is free, at which point they can begin the collision- avoidance cycle to reserve the network for their transmissions.

Price and Availability

The suggested retail price of $50 for AppleTalk includes the AppleTalk connector and two meters of cable; additional ten-meter cables and connectors may be purchased.  AppleTalk will be available in March 1985 in the United States and Canada through all Apple distribution channels, and in June 1985 internationally.  During the second quarter of 1985, 100-meter cable custom-wiring kits will also be available.

AppleTalk* Personal Network Product Specifications
Maximum Number of Connections
Shielded twisted-pair
Passive drops
Operating Distance:
1,000 feet
230.4 kilobits per second
Link Access Protocol:
Carrier-sense multiple access with collision avoidance (CSMA/CA)
Frame Format:
SDLC (Synchronous Data Link Control)
Self-configuring, no user switches or action to identify devices
Operating temperature:    0 C to 40 C
Storage temperature:       -40  C to 70 C
Relative humidity:             5% to 95%

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