HP 2640

Hewlett-Packard
Industry	Computer hardware
Founded	January 1, 1939; 87 years ago
Headquarters	Cupertino, California, United States
Products	HP 2640A and HP 264X series terminals

The HP 2640A along with other models in the HP 264X lineup were intelligent, block-mode "smart" terminals designed for ASCII serial communication. These terminals, manufactured by Hewlett-Packard, utilized the Intel 8008 and 8080 microprocessor chips.

History

Launched in November 1974 with a retail price of US$3000, the HP 2640A was built around the Intel 8008 processor. It came equipped with 8 KB of ROM firmware and included 1 KB of RAM as standard, expandable to 8 KB through two additional 4 KB memory cards. In September 1975, Hewlett-Packard introduced the HP 2644A, a variant of the 2640A featuring mass storage via two mini-tape cartridges holding 110 KB each, priced at US$5000. The following year, HP released a more affordable version, the HP 2640B, at US$2600. Alongside it came three international editions tailored to specific language needs: the Cyrillic-focused 2640C, the Swedish/Finnish-oriented 2640S, and the Danish/Norwegian-targeted 2640N. These early versions operated on the slower 8008 CPU running at 700 kHz, which limited communication speeds to a maximum of 2400 baud. Production of the original 2640A and the 2644A ceased in February 1977, while the 2640B model remained available until August 1981.

In September 1976, HP unveiled the 2645A terminal supporting communication speeds up to 9600 baud and offering optional mini-tape cartridge storage. This model was priced at US$3500 without storage and US$5100 with it. The 2645A marked a shift to the faster Intel 8080A processor clocked at 2.5 MHz—a standard adopted by subsequent models. November of that year saw the release of the HP 2641A, designed specifically for APL programming language users. In April 1977, HP introduced the 2645R variant that supported right-to-left Arabic script display.

July 1977 brought the arrival of the HP 2648A graphics terminal, which added black-and-white raster graphics overlay capabilities. This was followed by May 1978’s launch of the programmable graphics terminal HP 2647A featuring an integrated BASIC interpreter. In October 1980, HP expanded its lineup with the HP 2642A—a model similar to the 2645A but equipped with a standard 5.25-inch floppy disk drive capable of storing up to 270 KB per diskette. The final iteration in this series was the HP 2647F programmable graphics terminal introduced in June 1982 as an enhanced successor to the 2647A; it incorporated the floppy drive from the 2642A and upgraded to an Intel 8085A CPU running at a clock speed of 4.9 MHz. Hewlett-Packard continued manufacturing terminals in the HP 264X family until early 1985.

Model number

In official HP catalogs, this terminal is most commonly listed as "2640A," occasionally appearing as "HP 2640" or "HP 2640A" (with a space after "HP"). Less frequently, it is referenced simply as "2640." Variations such as "HP2640" or "HP2640A" without spaces are incorrect but often found in external sources.

Functionality

The HP 264X series maintained its status as a favored terminal choice for HP1000 and HP3000 computer systems due to advanced capabilities that competitors like the VT100 lacked. These included offline form handling, multipage display support, and local data storage on selected models.

Its design featured a distinctive boxy shape with a widescreen aspect ratio aligned with punched card character lengths—emphasizing character form over conventional CRT ratios such as standard 4:3 formats. This approach resulted in higher production costs because of non-standard component requirements.

Text rendering benefited from half-pixel positioning within a seven-by-nine dot matrix grid, effectively doubling horizontal resolution and delivering smooth character outlines. The display offered excellent readability with scan lines that were virtually imperceptible.

The keyboard was detached from the main unit and connected via a thick cable; its flat-top keys resembled those found on HP's own 9800 series computers. It included alphabetic and numeric keys alongside cursor and editing controls, complemented by two rows of function keys positioned above. Although its bit-paired key layout differed from DEC’s VT100 terminal, it was well-regarded for extensive key functions. Later models introduced screen-labeled function keys supporting hierarchical menus for efficient navigation—an early example of interface design later seen in devices like Texas Instruments calculators and automated teller machines.

Internally, these terminals featured a motherboard accommodating plug-in daughter cards responsible for CPU processing, memory expansion, serial interfaces (either RS-232 or current loop), and optional peripherals such as tape drives. This modular architecture simplified field upgrades and repairs and bore resemblance to Apple II’s expansion system.

Manufacturing and quality testing took place at Hewlett-Packard’s Cupertino Data Terminals Division; their test facility contained racks holding up to five hundred terminals undergoing automated test sequences simultaneously.

The HP 2640 pioneered "block mode" operation akin to IBM’s 3270 terminals but compatible with ASCII serial protocols. Using escape sequences, it defined protected input fields that allowed users to enter data offline before transmitting it all at once via a SEND key. These fields could enforce alphabetic or numeric-only input—offering validation sophistication exceeding some contemporary forms software—and also supported teletype character mode without requiring specialized communications hardware.

Unlike traditional terminals that stored characters in simple arrays indexed by position, the HP 2640 utilized linked lists composed of dynamically allocated blocks containing embedded bytes for display enhancements such as underlining or dimming along with protected field markers. Later models adopted parallel bit structures for visual effects despite increased complexity in emulation logic. This innovative approach influenced sparse matrix data structures used in software like Twin spreadsheet applications.

The availability of multiple memory pages on these terminals anticipated features now common in DOS environments; page up/down keys were standard on PC keyboards years later.

Users could edit lines locally using an offline key before retransmitting them—effectively providing command line recall even when unsupported by host operating systems. Only user-entered input was retransmitted while prompts were excluded from sending. This capability evolved into what became known as "line mode." Additionally, formatted screens containing protected fields enabled local editing of form data that could be selectively sent back to host systems—minimizing screen redraws and cursor movement commands—a technique employed in systems such as TIM/3000 Air Call Computers.

Hewlett-Packard’s Printer Control Language (PCL) level 3 shared escape sequence syntax with these terminals; PCL later became foundational for HP’s first LaserJet printers.

Internal teams developed TinyBASIC interpreters for the HP 2645A and created assembler-based games including "Keep On Drivin'," Tennis, and Reversi. Plotters interfaced through HP/GL2 alongside TinyBASIC programming capabilities.

Models

The HP 264X lineup extended the capabilities of the HP 2640A with several significant variants:

The HP2644A featured 3M mini cartridge tape drives, allowing quicker data transfer rates than conventional paper tapes. Subsequent versions integrated floppy disk drives and supported form-based drawing with computational abilities such as intersection calculations. Programmable function keys displayed values and were labeled using scroll-locked lines on the screen for enhanced usability.

The HP 2648 served as a graphics terminal equipped with hardware zoom functions and "autoplot" features. It maintained distinct memory banks for graphics and text, which users could switch between independently.

The HP 2647 incorporated a customized Microsoft BASIC interpreter that included native HPGL (AGL) plotter support, pioneering business-oriented charting on microcomputers with features like 3D cross-hatched pie charts. It provided multiple software packages addressing graphics, statistical computations, project management, and general utilities, facilitating business applications such as the PC-based Chartman.

The HP262X series introduced a "periscope" design characterized by soft key labels, a hierarchical setup menu, a 12-inch display, and an optional internal thermal printer. The HP-125 Dual Z80 CP/M system adopted the HP 2621 terminal’s form factor and emulation capabilities. Meanwhile, the HP-150 integrated the functionality of the HP 2623 terminal into a compact unit with a 9-inch screen.

The HP2382 repackaged the HP 2622 into a more compact format featuring a 9-inch display. The HP-120 combined elements of the HP-125 within the HP2382 chassis design.

The "Therminal," an early project from HP's Vancouver division, was a screenless thermal printing terminal that utilized tape cartridge local storage; however, it did not achieve commercial success.

HP also developed an ambitious color graphics terminal priced above the monochrome HP 2647 workstation. Despite substantial investment in development, this model experienced limited market adoption.

In the end, HP offered a cost-effective variant of the HP 2640 series. Modern terminal emulators continue to replicate the sophisticated feature set introduced by these terminals in the late 1970s.

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