pocket pc

4 Articles

Ancient Pocket Computer Gets A Serious Serial Upgrade

March 25, 2025 by 9 Comments

[Robert’s Retro] is one of those great YouTube channels that shows us the ins and outs of old and obscure computers. [Robert] likes going a step beyond the traditional teardown though, repairing and upgrading these old machines. His latest project involves giving the ZEOS Pocket PC a fully-functional serial port. 

If you’re unfamiliar with the ZEOS Pocket PC, you might know it as the Tidalwave PS-1000—it’s a pretty straightforward clone. Originally, these machines could be had with a proprietary serial adapter to enable them to interface with external peripherals. However, like most obscure cables and connectors from three decades ago, they’re virtually unobtainable today.

To solve this problem, [Robert] decided to hack in a traditional DE-9 connector instead. Commonly referred to as the DB-9, this is the most common serial port design used on IBM PCs and compatibles. Getting the larger port into the compact PC required some careful hacking of the case, as well as delicate soldering to hook up the pins to the right signals on the tightly-packed motherboard. This video does involve cutting some vintage plastic, but overall it’s a very neat mod that is handled with due respect and care.

This isn’t the first time we’ve seen him upgrade a classic portable computer, either.

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Tandy Pocket Computer Assembly Is… Weird

February 12, 2024 by 21 Comments

Radio Shack had a long history of buying things overseas, having their name slapped on them, and selling them in the United States. That was the case with the Tandy Pocket Computers, which were in that awkward space between calculators and full-blown computers. Like many computers of those days, if you wanted to do anything interesting, you needed to turn to assembly language. But as [Old Vintage Computing Research] recalls, the assembly for these little devices was very strange, even for an assembly language. He found out that there is a reason it is so strange and shares it in a deep dive into the device’s machine code history.

The story starts with the Japanese government. In 1969, the ministry in charge of such things decided that it wouldn’t be fair for people who knew a particular computer to have an advantage when taking the Information Technology Engineer exam. So, logically, they made up a fictitious instruction set and architecture for the test. Since no one used it, no one would have an unfair advantage.

However, eventually, Japanese manufacturers started making computers that used the architecture. The architecture was COMP-X, and the assembler was CAP-X. The post covers the history of machines either using the architecture or emulating it going back to the 1970s. It eventually winds up at the Sharp and Casio pocket computers that would wear Radio Shack livery in much of the world, especially the United States.

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Modern Demo For A Casio PB-700 Pocket Computer Plotter

August 13, 2023 by 9 Comments

[Fred] has a Casio PB-700 pocket calculator / computer, complete with the companion docking station featuring a four-color pen plotter, model FA-10, and a microcassette tape recorder, model CM-1. He really wanted to see what this plotter could do, but there were no demos that he could find. So despite only having one working pen, [Fred] took matters into his own hands and proceeded to make his own.

What if I made a program where I type what I want to draw and the PB-700 just draws it?