Nestar Systems, Inc., was an early independent manufacturer of pre-internet local area networks for personal computers from 1978 to 1986 and was considered[1] "a pioneer in the industry".

[2] by Harry Saal, Len Shustek, Jim Hinds, and Nick Fortis, to make networks that allowed sharing of centralized services like disks and printers[3] for the then-new personal computers: Commodore PET, Apple II, and Radio Shack TRS-80.

Annual revenue had grown from $318.000 in 1979 to $10,032,000 in 1984, but profitability had still not been achieved even though they were one of the top 10 PC local area network vendors[1] In August 1985 it was announced[9] that Nestar was to be bought by Net America, a Dallas-based startup common carrier founded by Sam Wyly, who also founded University Computing Company and was chairman of Sterling Software, Inc.

Nestar was instead acquired[11][12] a year later, in October 1986, by Digital Switch Corporation (soon to become DSC Communications) of Plano, Texas.

At the time of the acquisition by DSC, Nestar founders Saal and Shustek left the company and received the rights to a Nestar internal local area network test tool that they developed into Network General's Sniffer protocol analyzer.

In August 1979 Nestar had created a wholly-owned subsidiary called "Palo Alto ICs'".

We couldn’t get a business to buy Apple II’s or Commodore PETs or TRS-80s, because they were toys... We had some modest success selling to schools, who used them for kids for training and games and whatnot.

Unlike for Ethernet, the separate carrier line was asserted between related data transmissions so that the ACK or NAK for a packet could follow immediately without having to reacquire the channel.

The transmission speed was 240 kilobits per second, which was the fastest rate that could be supported by a software-driven network interface running on an 8-bit processor such as the 6502 in the Apple II.

The processor was a version of the Sun Microsystems 8Mhz 256KB Motorola 68000 Multibus microprocessor board, which had been licensed to Codata and other manufacturers.

PLAN 2000 was a software package that allowed 2 to 4 IBM PCs to share the hard disk and printer of one of them.

Unlike the prior systems, Nestar advertised[40][41][42][43] the PLAN Series primarily to corporations, who were increasingly adopting the IBM PC for desktop use.

In a later article [49] they said of the PLAN 4000 file server, "In its sober gray vertical cabinet, it looks for all the world like a trash compactor.

Inside, however, beats a heart of the purest silicon...Our impression of the Nestar is one of quality—albeit expensive—workmanship and high performance."

Competitors for some aspects of Nestar's PLAN series included Corvus Systems, Novell, 3Com, and Ungerman-Bass.

In August 1979 a wholly-owned subsidiary of Nestar called "Palo Alto IC's" released the "BASIC Programmer's Toolkit",[52] a collection of programming aids for the Commodore PET computer distributed as a hardware read-only-memory (ROM).

The Toolkit became extremely popular, and in the first six months there were over a million dollars in retail sales, which attracted the production of unauthorized copies by counterfeiters.