Communication ports¶

Over the years, CASIO calculators have had various communication ports on them.

3-pin port¶

../../_images/port-3pin.png — Representation of the 3-pin port and corresponding connector.¶

This communication port has been introduced with the fx-7800GC and fx-8800GC (1992), and has been on every graphical CASIO calculator since then.

The 3-pin communication port is a TRS Jack 2.5mm port, where:

The tip is the RX port.
The ring is the TX port.
The sleeve is the GND port.

This port is used for serial communication with calculators, PCs, and other CASIO units; see Serial transport for more information.

The serial communication over RX/TX is similar to RS-232, with a voltage level of 0V (GND) for logical 0, and for logical 1, either +4.5V for older models, or +3.3V for newer ones.

PXH-A16 port¶

This port was used on CASIO’s Pocket Viewer and calculator units in 2003 and 2004, before they switched to USB Mini-B ports. It was conceived and manufactured by Honda connectors, with the following components:

PXH-A16LMYG being the board receptable connector;
PXH-A16FSG being the cable plug connector;
PXH-A16SP being the backshell.

The port makes the calculator able to behave as both a USB and a serial device, depending on the type of cable plugged into it. See Serial transport and USB transports for more information.

In the case of a USB Type-A to PXH-A16FSG cable, the pinout is the following:

USB Type-A                 PXH-A16FSG

                     +V
1 RED ----------------------------- 1

                  DATA (-)
2 WHITE --------------------------- 5

                  DATA (+)
3 GREEN --------------------------- 6

                    GND
4 BLACK -------------------------- 16

USB Mini-B port¶

With the introduction of the fx-9860G and Classpad 300+ in 2005, CASIO started adding an USB Mini-B port to its calculators, replacing in the case of the Classpad the PXH-A16 port.

See USB transports and USB detection for CASIO calculators for more information.

USB Type-C port¶

With the introduction of the Graph Math+ in 2024, CASIO replaced the USB Mini-B port with a USB Type-C port.

This port however still presents the same interfaces as USB Mini-B.

See USB transports and USB detection for CASIO calculators for more information.