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Xerox 2700 Distributed Electronic Printer
The Xerox 2700 was a compact laser printer manufactured by Xerox Corporation beginning in 1982. Targeting offices and small data centers worldwide and based on the Xerox 3300 copier, the 2700 printed at 300 dots-per-inch on cut-sheet paper at up to 12 pages per minute (ppm) one-sided, landscape or portrait. Print volume rating was nominally 15,000 per month but its productivity proved far greater than that of the base copier and some installations printed more than 100,000 pages per month. === 1 History ===

The first successful products based on the xerographic process were for office copying applications and each had lighting and a camera-like subsystem to form an optical image on a charged photoconductor and mechanisms to develop the charge image, transfer the developed image to paper and fix it. By about 1961 there were experiments under way at Xerox to explore other applications and imaging methods. The first product result, in 1964, was LDX (Long Distance Xerography)  a facsimile system which used a CRT (cathode ray tube) as an imaging source. A version for computer printing was offered as the XGP (Xerox Graphics Printer) 3, but higher performance was elusive. The Xerox 1200 4, in 1973, used an optical analogue of the drum line printer – a spinning optical character drum and a row of xenon tubes whose flashing was timed to project the required characters onto the photoconductor. It was ingenious and unique. The great advance, of course, was laser imaging, first offered in a computer printer by Xerox as the 9700 in 1977 based on the 9200 5 copier product and digital imaging technology from PARC. At the time even laser printers were marketed as “electronic printers” because of the variety of technologies and potential concerns about laser safety.

The Xerox 9700 was huge, fast (120ppm), very expensive, and soon became the premier electronic production printer. A smaller laser printer, the 5700, was introduced in 1980, but now regarded as an experiment in innovation. The Xerox Alto and Star (Xerox 8010) developed at PARC, although expensive and poorly understood by most of the corporation, pioneered enduring technologies for personal computing and, with the 8044, for laser printing in the office, although only as part of an 8010 system, which was not a commercial success. The laser-xerographic component of the 8044 (known as the XP-12) had been developed by the Xerox Printing Systems Division, whose engineers were charged with coming up with a relatively low-cost product which could be used with popular computers in offices and small data centers. === 2 Design and Development ===

By 1980 the XP-12 “marking engine” was a sound basis for the new product. It was in a suitably-sized cabinet containing the xerographic subsystem, laser scanning module (known as the ROS, for Raster Output Scanner), paper handling, keypad, digital video interface and power supplies. Straightforward revisions were made to these, but the principal challenge was to engineer an electronics subsystem (ESS) or controller that would present a printer interface having industry standard electrical and protocol characteristics and deliver suitable digital video to the marking engine. In addition, extensions were required to the industry standard protocols to accommodate the multiple fonts, page formatting and graphics enabled by laser printing technology.

The balance of functionality, cost targets and manufacturability led to a single-board implementation and a receptacle for up to four read-only memory (ROM) cartridges containing additional font data or software, all within the existing cabinet. Since conventional printer protocols used control characters and “escape codes” (the ESC character followed by another character), the laser printing extensions were additional escape codes. The resulting Page Description Language (PDL) became known as Xerox Escape Sequences (XES). For situations where the escape character could not be used a protocol was provided for using a surrogate, called the “User Defined Key” or UDK. The software had a formal logical structure, but there was insufficient hardware, and no need, for a general-purpose operating system. The most apparent hardware limitation in practice was to page complexity. The xerographic process is, in effect, page-oriented. Once page imaging is started video data must be delivered regularly, scan line after scan line, at the characteristic speed of the process, until the page is complete. A page with many characters, fonts and graphics could exceed the power of the ESS to deliver video data as required. At that time a full page buffer would have been prohibitively expensive. Instead, the 2700 used two “band buffers” in the ESS memory of 32 scan lines each for alternately assembling and outputting the video data. This proved enough in practice for most applications. Should a page be presented that exceeded the processing power and memory available and printed with errors, the shortfall would be reported on a summary sheet at the end of the print job. === 3 Specifications ===

GENERAL Xerographic laser printer, 12 pages/minute, 300x300 dots/inch

Dual Selectable 250-sheet Input Paper Cassettes, 500 Sheet Offsetting Stacker

Multinational regulatory and language compliance

Key elements: CPU: Intel 8086; Input/Output: Intel 8089 & Zilog Z80; RAM: 64kB or 256kB; ROM: 32kB on board, and up to 4x32kB in plug-in cartridges; 5mW HeNe Laser/Polygon Illuminator; long-life photoreceptor; replenishable toner; radiant fuser

COMMUNICATIONS INPUT OPTIONS

RS232C INTERFACE, ASCII or EBCDIC

Serial Bisynchronous Interface Protocol (IBM 2770/2780/3780 emulation)

Serial Asynchronous Interface Protocol

PARALLEL ON-LINE INPUT OPTIONS

Centronics 100 Parallel Interface & emulation

Dataproducts 2260 Parallel Interface & emulation

PAPER AND FORMS

16 to 24Ib. bond 8 ½ x 11 or A4 cassettes included 8 ½ x 14 and other sizes optional Preprinted forms handling Custom Electronic Forms Creation and Merging

PRINT FEATURES

Support for Standard Protocols, plus Xerox Escape Sequences (XES) Page Description Language (PDL) for Text and Graphics Formatting and Printer Control; demographics subject to CPU/memory limitations

FONTS

Two standard font sets included: 189 character Titan-10 ISO portrait font, 101 character XCP14 landscape font, U.S. ASCII and ISO 6937 character sets, Optional plug-in Font Cartridges: Cartridge Options: 32 & 16K bytes, Parallel Printer: Maximum 4 cartridges, Serial Printer: Maximum 3 cartridges, Optional Down-loadable Fonts: Various font styles and sizes, fixed and proportional spacing, 4 to 124 point font range, 6 to 24 point standard font library; Page Maximums: Up to 10 fonts specifiable per page, If redefined within the page, up to 15 fonts per page

PHYSICAL CHARACTERISTICS

Dimensions (Max): Width/Depth/Height/Weight 26in./26in./36in./295 lbs.

Environmental: 50oF to 90oF (10oC to 32oC) 15% to 85% Relative Humidity Standby: 350 Watts Printing: 1150 Watts

Electrical: USA and Canada: 120 volts, 60 Hz, single phase, 15 amp circuit International: 220-250 volts, 50 Hz, single phase, 1.2 kVA === 4 References ===

2.	Morehouse, H.G.; Shoffner, R.M.; An Experiment in Library Application of Xerox LDX Facsimile Transmission Equipment. Phase I: Planning and Analysis; California Univ., Berkeley. Inst. of Library Research; 1966-Jun-13. Retrieved 6 November 2021.

3.	Greenspun, Philip; The Dover; Philip Greenspun's Homepage : Philip Greenspun's Homepage Discussion Forums : NE43 Memory Project; January 4, 1998. Retrieved 6 November 2021.

4.	Mitchell, John N. Jr; The Xerox 1200 Computer Printing System; Computer, Volume 8, Issue 9, September 1975 pp 40–48. Retrieved 6 November 2021.

5.	XEROX INTRODUCES 9200 COPYING UNIT; The New York Times; April 30, 1974. Retrieved 6 November 2021.

=== 5 External Links === •	Xerox 3300

•	Xerox.1987.FactBook.odd.pdf •	Xerox.1987.FactBook.even.pdf •	Xerox Printers – Computerworld March 22 1982 •	Word’s Eye View - The Ultimate IBM – PC Mag - Jul 1983 p.130-132

Ruston7 (talk) 00:43, 9 November 2021 (UTC)