On the genesis, life and death of the HP 48.

In 2003, an era ended. The technology giant Hewlett-Packard Company, Palo Alto, Calif., announced the end of production of the HP 48, the scientific calculator/computer used by numerous surveyors-and which surveyors had ranked above most other devices in its class. What was even more upsetting for surveyors was that HP didn't announce a product for replacement. For three decades Hewlett-Packard had been a standard for scientific calculations in a number of disciplines. The unit was well-suited for a surveyor's fieldwork and was a particularly applicable tool for solving problems in the field and office for many surveying firms.

From HP's development of calculators, businesses were founded and products were created that specially served the needs of surveyors. The calculator line provided a new starting point for enterprising inventors and developers to market field computing products to surveyors.

Steve Chou (left) and Dennis York display the HP 41 and the HP 48.

In the Beginning

The HP brand has been one of the gold standards of manufacturers' names associated with surveying. This began in 1972 with the introduction of the HP 35, the first electronic handheld calculator that enabled trigonometric and logarithmic functions as fast as one could press the keys, in addition to the more basic things like taking square roots (or any root for that matter). Before the HP 35 (whose name came about because it had 35 keys), handheld electronic calculators mostly did the four basic algebraic functions, and the "scientific" ones squared numbers and did square roots. Desktop units had been produced by HP since 1968, but the HP 35 was introduced because Bill Hewlett, the CEO of HP in the early '70s, believed market studies that showed little demand for a handheld scientific calculator to be wrong.

Until the release of the HP 35, surveyors, unless they spent big bucks for electronic or mechanical calculators, used trig and log tables to do most of their calculations. But even more amazing than removing the tedious table lookup from the calculations was the fact that the HP 35 allowed surveyors to make calculations in the field that they had only dreamed of until that point. The 1970s and 1980s also saw a brief spurt of activity at HP in the development of software, EDMs (HP 3800 series) and total stations, culminating in the HP-3820 (the inkjet printer later developed wasn't the first time HP used that number). In fact the term "total station" comes from HP's name for their products that integrated angle and distance instruments.

The HP 35 was quickly followed in 1973 by the HP 45. It introduced the ability to work in degrees and grads, not just radians. The HP 45 also introduced polar-to-rectangular conversions and the now ubiquitous H.MS key that allows simple conversion of sexagesimal numbers (degrees-minutes-seconds) to and from decimal degrees. With nine memory registers and the summation function, surveyors using the HP 45 could accumulate latitudes and departures without actually writing them down. Averages and standard deviations could also be calculated. Surveyors didn't think it could get any better.

HP 48GX photo compliments of TDS. All other calculator photos courtesy of The Museum of HP Calculators, www.hpmuseum.org.
But it did. HP introduced one calculator after another that improved on the previous one; they even produced desktop versions of some. Following the HP 45 came the HP 65 programmable, the HP 55 programmable with quartz timer, a number of 20-series calculators (many with continuous memory that saved data in the registers even when switched off), the HP 67 magnetic card programmable (and its HP 97 desktop sibling), and, beginning in 1978, a whole slew known as the 30-series. It just didn't seem that HP could improve on its third generation. But improve they did with the HP 41 in 1979.

The HP 41 was the company's first alphanumeric calculator. It started to blur the distinction between calculator and computer. The unit had the capability to create user functions and to rename (or more correctly, re-position) existing functions to other keys. For instance, a user could take all the keys in the left-hand column, which included the +, -, x and division keys, and assign them to other keys. The HP 41 also had a greater expanded memory capability and a low-power LCD display. And it had four ports that surveyors thought were practically magical.

Those four ports allowed users to plug in for extra memory, pre-programmed software modules, a magnetic card reader, an optical wand and printers. Plugging the HP-IL (for Interface Loop) module into one of these ports allowed devices that complied with the HP-IL standard-including a disk drive, printer and third-party devices-to be connected in a loop.

Fast-forwarding to the last of a glorious HP-developed line, the now legendary HP 48 was introduced in 1990. While almost all previous HP calculators were reverse Polish notation (RPN) operation, the HP 48 computing system saw the advent of Reverse Polish Lisp (RPL) operation in a portable unit. RPL was developed as an internal programming language for the HP 18C introduced in 1986. It was actually user-accessible with the HP 28 series introduced in 1987. The HP 48 (as its name implied) brought elements of the HP 41 and HP 28 together. It had a large 64 x 131 pixel graphics screen. And the equation solver and matrix entry, among other capabilities of the HP 28, now had more room to "stretch."

HP-based Surveying Software

In 1983, while teaching at the University of Missouri, I was hired by The Lietz Co. (later acquired by Sokkia and now called Sokkia Corporation), to develop a data collector software program for its EDMs and semi-total stations. Semi-total stations (also known by some as "manual total stations") were optical theodolites with integrated EDMs. Distance could be electronically transmitted to a data collector, and the horizontal and angle values keyed in by hand. Some semi-total stations even had an electronically sensed vertical angle that could be electronically output as well.

Bob Martin, vice president-products for Lietz, agreed during discussions with me that a data collection software based on the HP 41 made sense since surveyors were flocking to the hardware device for their field and office calculation needs. Surveyors particularly liked it because, being the individualists most are, they could write their own surveying programs. But this effort eventually was diverted away from the HP 41 platform when Mike Beckingham, managing director of Sokkia's Australian subsidiary, created the SDR1 electronic data collector, the first in the series of Sokkia's trademarked Electronic Field Books, with Alan Townsend, manager of a New Zealand company, Datacom Software Research (later to become Trimble New Zealand). My work left the HP environment at that time when I joined with the SDR1 group and Bob Martin to develop the SDR2, and eventually the SDR20 series, SDR33 and SDR31. The Sokkia line of data collectors attracted a lot of attention because it provided innovative features and had, at least for those times, a superior user interface that allowed surveyors to get up and running with it quickly. But it was an expensive product-initially just under $4,000, and it originally only worked with other Sokkia products.

Stanley Trent

Enter Stanley Trent and Harold Hayes

In East Tennessee, one of those individualist surveyors, a man named Stanley Trent, worked on his dream-a data collector based on the HP 41 that would perform all the critical field functions, including hand-entered capture of whatever data a modern surveying instrument would output. With 22 investors to bankroll his efforts, Stanley started a company called Surveyors Module Inc. (SMI) to develop and market his data collection product.

Trent was stretched thin conducting the development and the marketing efforts for his product called the CO-OP Module, which was introduced in 1983, so he went back to one of his original 22 investors named Harold Hayes for help. Hayes headed Hayes Instrument Co., a small business that he says was "still in my garage at that time and still struggling, [but] was making a little money." Hayes considered Trent's request for additional investment. He realized that most of Trent's other investors were surveyors who continued to rave about his product. So, he says, he "refreshed Trent's bank account with a $10,000 [advance] purchase of modules and began helping Stanley develop and market the module." This is when, as Hayes says, "things began to get better." Hayes carried the product through Hayes Instrument Co., and helped Trent market it in other ways, generally helping to make the CO-OP Module a success.

Trent made many trips to Corvallis, Ore., to meet with his module suppliers. On one of these trips, he met Dave Conklin, co-owner of a company called Firmware Specialists Inc. (FSI) in Corvallis. Conklin, a former HP employee, and another ex-HP em-ployee named Steve Chou, who had worked on the HP 41 and HP 75, met Trent in the late '80s. Conklin told Trent that he could develop an electronic interface for the HP 41 that would enable it to communicate with most total stations that used the RS-232C protocol. Because Trent's product was pushing the memory limits of the HP 41, and because addition of an RS-232C interface would consume a lot more power than the HP 41 alone, Conklin also told him that this interface device could be built with additional memory and battery power to overcome those problems. Lietz' SDR series could already communicate with Sokkia total stations using RS-232C. Trent saw a way to improve on this function even further. Being independent, he could provide electronic data collection for all brands of total stations, not just Sokkia instruments alone.

Harold Hayes
Trent went back to Hayes. He couldn't dream of investing in this device proposed by Conklin, but asked Hayes if he would be interested. As a struggling young high-tech company, FSI was desperate for revenue. Conklin flew to Knoxville to meet with Hayes and took with him a mock-up of the device. His pitch was so convincing that Hayes gave him a $30,000 purchase order for the first 50 units. Without this, FSI would never have been able to put the interface into production. In six weeks, Hayes received his first unit and teamed it with software that Trent and Chou had updated to facilitate electronic downloading of data from a total station. "It worked right out of the box," Hayes says. "We called it the Hayes HP 41 data collector."

There's a tieback to Sokkia/Lietz in this story: after the SDR2 was on the market, Lietz's Bob Martin and I had been tasked to find an RS-232C interface for the HP 41 so it would work with Sokkia/Lietz instruments. Even though the SDR2 was a successful product, many surveyors asked Lietz for a way to interface the HP 41 with their home-built data collection programs to their total stations. Looking in HP country, we found a small start-up company founded by former HP employees. It was, indeed, the company FSI! Lietz contracted with FSI to develop, build and manufacture the HP IL to RS-232C interface. And it was this (non-exclusive) technology that FSI developed for Lietz that was leveraged into the HP 41 interface offered to Hayes.

With the successful creation of the interface, Hayes Instrument Co. introduced the Hayes HP 41 data collector to the world. With FSI (primarily Steve Chou adding drivers and resolving other software issues) now helping to create the HP 41 program modules, generically called CO-OP 41 modules, they took on the job of marketing and selling the module and the HP 41 interface in a data collection package in 15 states west of the Mississippi. Hayes marketed the product, now remembered as the SMI CO-OP HP 41 module, in Tennessee and five surrounding states; SMI covered the rest of the United States. The product initially sold by SMI was only the module. Trent then realized he would have a more complete product by selling the "data collector" that included the HP 41 interface, module, cables, instruction manuals and other accessories in one neat package. So, he negotiated with Hayes for the right to incorporate and sell the Hayes HP 41 data collector with his module, and according to Hayes, "the Hayes HP 41 data collector became the CO-OP 41 data collector in SMI's territory."

Bernie Musch

The TDS Link

During a period of flux, Chou left FSI in 1987 taking Bernie Musch, the former HP calculator development manager, with him to create a company to serve surveying software needs. They both took a surveying course at Oregon State University. Chou, the chief programmer of the company now known as Tripod Data Systems (TDS, Corvallis), became involved in the development of software improvements for the CO-OP module, especially the drivers to enable it to communicate with an ever-expanding array of electronic instruments. Musch managed the business aspects of the company. By then (1987), TDS was marketing the module under its own name and had added some software differentiation.

The complete separation between TDS and SMI (and Hayes) occurred with the introduction of the HP 48. TDS was able to get the help of Hewlett-Packard in advance of the introduction of the HP 48 to begin the job of "porting" the HP 41 software to the new platform. TDS even got advance prototypes several months in advance of the formal introduction of the product. SMI hired Trent's son, Ken, to begin its own development to compete with the TDS product.

Bill Martin (left) and Dave Scribner.

HP 48-based Development at TDS

The HP 48 platform helped TDS to power its way to an overwhelming success with field data collection products for surveying. The company has since added PC-based software products, GIS software, and even created the Ranger from scratch, after recognizing the need for even more powerful software and processing power than the HP 48 could support or provide. Later, in 2003, TDS introduced the Recon data collector to replace the discontinued HP 48.

But the early days of the HP 48 were heady and somewhat uncertain at TDS. Dennis York, the software section manager at HP's calculator division in Corvallis, took a prototype HP 48 to his friends at TDS in late 1989. The market for calculators was such that surveying did not dominate the engineering or marketing of the HP calculators. But Hewlett-Packard did recognize that the HP 48 had more potential in the surveying market than HP could hope to take advantage of without third-party help. Development and marketing of a surveying oriented product on the HP 48 was (by now) outside of HP's field of expertise. Wanting a head-start for the HP 48 by having ready-made applications at the time of introduction, York thought he'd ask the folks at hometown TDS to take a look at it. TDS was selected because they seemed best positioned technically, promotionally, financially and managerially to succeed. Musch and Chou were initially dubious of the extra investment this product would take. The old HP 41 code would have to be re-written at best and "ported" at worst. Both options were expensive. York (today a TDS employee) recognized that surveying was one of those applications that could really prove the HP 48 by taking advantage of it. Finally, with the offer of a development system from Hewlett-Packard, TDS decided to tackle it. Prior to the introduction of its Ranger and Recon data collectors, the HP 48 product had been TDS' biggest success.

The Discontinuation of the HP 48

When Hewlett-Packard announced the discontinuation of the HP 48 in 2003, the company only gave six months' notice and production had actually stopped. "We heard through the grapevine that the HP 48 was being discontinued, but there was no official announcement until 2003," says Bill Martin, then-marketing manager, now president of TDS. Recognizing the undying appreciation of surveyors for software based on this platform and having sold more than 100,000 modules during the lifetime of the product, TDS immediately asked Hewlett-Packard how many they could get of the remaining stock. After selling the HP 48-based products for more than 10 years, and having so many surveyor customers committed to the platform, "we wanted to do what we could to make sure that as many of the remaining new HP 48s in inventory would go out to TDS customers," Martin says. Together with product sourced from other wholesalers, TDS managed to get its hands on almost 2,500 units. The last HP 48 was sold in March 2004-fittingly to Hayes Instrument Co. According to Martin, Hayes has been one of TDS' best dealers with most likely the largest HP 48 customer base.

According to Eddie Clanton, president of Hayes Instrument Co., "When HP announced the 48's discontinuation, panic broke out. We looked everywhere and finally found that TDS had taken a stock of them. We had a lot of survey cards and accessories for the 48 but no 48s! Needless to say we put in an immediate order. And they've been selling like hotcakes. Now we're down to the last handful. They'll probably be gone by the time this shows up in print."

A Beginning to An End

For surveyors, the powerful line of HP calculators introduced in 1972 concluded when the HP 48 was discontinued. Hewlett-Packard has not offered a new product to fill its shoes, and due to this void, there are a few contenders for the role of successor. Several software vendors with products designed for surveying that run on the HP 48 platform now have products that work on platforms of some Windows variant (CE, Pocket PC, etc.). The new platforms are, for the most part, much more rugged than any of the HP calculators, and are water, dust, shock and vibration proof to a degree that is much higher than many of the HP ancestors. Life for surveyors can and will go on without the HP 48 and its predecessors they've come to love. But in-the-field computing will forever be indebted to the indelible HP legacy.


In 1990, Harold Hayes "wisely decided to get out of the software market, and began buying data collectors from TDS, and later SMI," Hayes says. "The HP 48 is gone, but TDS lives on." Bernie Musch, co-founder of TDS, passed away in 1992. Dave Scribner then joined TDS as president (and partner). TDS was acquired by Trimble Navigation Ltd. (Sunnyvale, Calif.) in 2000. Scribner retired in 2003 to be succeeded by Bill Martin. SMI was acquired by Eagle Point Software in 1999. Stanley Trent passed away in early 2004. Steve Chou continues his work at TDS as vice president of product development.