HP 39gII+

HP 39/40 series
Company type	Product line
Industry	Consumer electronics
Predecessor	HP 38G
Founded	2000
Founder	Hewlett-Packard
Headquarters	Palo Alto, United States
Area served	Worldwide
Products	Graphing calculators (HP 39g, HP 40g, HP 39g+, HP 39gs, HP 40gs, HP 39gII)
Owner	Hewlett-Packard

Adapted from the English Wikipedia article HP 39gII+, available under CC BY-SA 4.0Updated 8 August 2025

HP 39/40 series represents a line of graphing calculators developed by Hewlett-Packard, succeeding the HP 38G. Comprising six distinct models, each device offers algebraic entry modes and supports numeric analysis, with varying degrees of symbolic computation capabilities. Designed primarily for high school learners, these calculators enable the transfer of APLETs or E-lessons via cable or infrared connections—software tools aimed at enriching mathematics education through interactive graphical and numerical methods.

HP 39g

Introduced in 2000, the HP 39g (F1906A) includes the following specifications:

Processor: 4 MHz Yorke (Saturn architecture)
Connectivity: Proprietary infrared and serial RS-232
Memory: 256 KB RAM
Display: 131 × 64 pixels
Comes with a protective hard cover
Offers limited symbolic equation solving features

HP 40g

Also launched in 2000 alongside the HP 39g, the HP 40g (F1907A) operates on the same OS but benefits from enhanced software supported by its hardware configuration. Its design mirrors that of the HP 49G/39G series, featuring a rubber keyboard and incorporating the sophisticated computer algebra system (CAS) known as Erable from the HP 49G.

Notable characteristics include:

Absence of infrared communication; only serial RS-232 available
Capacity limited to 27 variables
Equipped with an equation editor and an advanced CAS
Simplified interface designed for straightforward mathematical analysis without complex flag adjustments
Usage restrictions apply: prohibited on the ACT, but allowed on the SAT since 2019

HP 39g+

Released in September 2003, the HP 39g+ (F2224A) introduces enhancements in processing power and connectivity options:

Processor: 75 MHz Samsung S3C2410X (ARM920T core)
Memory: 256 KB RAM and 1 MB flash storage
Communication: USB Mini-B port supporting Kermit or XModem protocols, plus IrDA
Power supply: Three AAA batteries with a CR2032 battery for memory retention
Display resolution: 131 × 64 pixels
Does not include a hard cover
Symbolic equation functionality remains limited

Despite utilizing an ARM processor, this model's operating system predominantly simulates the Saturn-based OS from the HP 39g at higher clock speeds. Unlike previous versions, the CAS present in the HP 40g is completely omitted rather than disabled.

HP 39gs

The HP 39gs (F2223A), launched in June 2006, boasts a 75 MHz Samsung S3C2410A (ARM920T core) CPU, along with 256 KB RAM and 1 MB flash memory to facilitate firmware updates. It supports connectivity through USB Mini-B ports (compatible with Kermit and XModem), IrDA infrared, and a four-pin asynchronous TTL serial interface. Powered by four AAA batteries supplemented by a CR2032 backup cell, it features a display of 131 × 64 pixels and comes with a hard cover. The operating system emulates Saturn chip behavior on ARM hardware to achieve faster performance while maintaining similar capabilities to the HP 39g. Symbolic equation solving remains restricted.

HP 40gs

Debuting in mid-2006, the HP 40gs (F2225A) shares its hardware base with the HP 39gs, including a 75 MHz Samsung ARM processor and 256 KB RAM. However, it doubles flash memory to 2 MB to accommodate more sophisticated CAS software. This model excludes infrared communication but includes an equation editor alongside an advanced computer algebra system designed for users requiring robust symbolic computation functions.

HP 39gII

Introduced in October 2011, the HP 39gII (model NW249AA) features an upgraded 80 MHz Freescale STMP3770 processor based on the ARM926EJ-S architecture. It comes equipped with 256 KB of RAM and a generous 128 MB of flash storage, of which roughly 240 KB of RAM and up to 105 MB of flash are accessible to users. The device includes a high-resolution monochrome LCD screen with a pixel dimension of 256×128. For connectivity, it utilizes a USB-OTG Micro-AB interface. To enhance computational efficiency, its BCD arithmetic libraries were rewritten in native C, replacing earlier emulation techniques. The calculator supports a programming language similar to Pascal, serving as a forerunner to the HP Prime’s HP PPL, incorporates a 128-level stack, and offers Unicode (UTF-16) compatibility. There are two different labeling styles available for the key.

A more advanced version, the "HP 39gII+" with Computer Algebra System (CAS), was nearly finalized but ultimately discontinued after Freescale ceased production of its processor. This development prompted additional redesign efforts that eventually led to the debut of the color touchscreen and more powerful HP Prime model launched in 2013.

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