Casio Serial Cable Components

This Casio serial cable circuit uses widely available low-cost components for the build, and many hobbyists will already have some of the components, which they may be able to use to lower the cost further. In my project, the MAX232CPE chip was recycled from an old modem back in 2000, and I always use it for projects such as this. These chips cost over four pounds today; hence, it is worth recycling components if you are a hobbyist.

Parts List

1N5819 Schottky Diode

General-purpose diodes such as the 1N4148 will exhibit a forward voltage drop between 0.6 V to 1.7 V. A Schottky diode such as 1N5819 will exhibit a voltage drop between 0.15 V to 0.45 V, which is much less and therefore desirable. These types of diodes are also fast switching making them ideal for this application.

Zener Diode

A 4.7 V Zener diode with a power rating of 0.4-watts produces a regulated 4.7 V supply voltage for the circuitry. For more information regarding this component, please refer to the Zener Diode Series Resistor Calculator article.

Resistor

This is the 47 Ω metal film resistor used to produce a voltage drop for the Zener diode.

Electrolytic Capacitor

Chip Socket

A chip socket is often a good idea if you plan to make many serial interface circuits. You can then reuse the chip on different projects.

DB-9

DB-9 sockets and plugs are expensive; hence, a recycled one is much better.

Board

A very small board for mounting the components is required, and this one has 14-holes × 10-holes.

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