The hidden port of the Nintendo Entertainment System has found a use. What is the project?

39 years ago, the Nintendo Entertainment System (NES) was released in the USA - an 8-bit console with support for two removable controllers. Not all console owners know that it has a 15-pin expansion port: located at the bottom of the device. As far as is known, Nintendo engineers were going to develop accessories for it. But they (the accessories, not the engineers) never went on sale. Now, it seems, this port has found a use.

What is this port and why is it needed

Initially, the 15-pin expansion port at the bottom of the Nintendo Entertainment System (NES) console was conceived as a way to expand the capabilities of the device. How? By adding peripheral devices. It was planned to connect light guns, 3D glasses, keyboards, additional controllers, and other accessories to it. Modems were also being developed: with them, it would be possible to access a specialized network that was used in the 1980s in Japan.

But the NES expansion port never received commercial use. In the Famicom, the Japanese version of the console, it was covered with a protective cover. The plastic plug could be removed. Then it was completely abandoned in the NES, the version of the console for the USA. The port was made inaccessible to the owner.

But NES fans and electronics enthusiasts remembered the port. Some of them found a use for it, although very limited. So to speak, just for fun. A few examples are below!

Three interesting projects

Sending messages on Twitter (now X)

In 2015, a DIY enthusiast named Trapper McFerron developed an unusual system: through the Nintendo Entertainment System (NES) console, it was possible to send tweets using the expansion port.

McFerron wrote specialized software for the NES, utilizing the Twitter API. Message sending was implemented through the console. The author also developed an adapter for network access. It all looked simply fantastic:

The project is non-commercial: the author created all this only for himself, as mentioned above, just for fun. If you have a loaf of bread, why not make a trolleybus out of it, right?

Sound generator for NES

A user with the nickname Perkka2 developed EPSM (Expansion Port Sound Module). This is a sound generator for the NES console, which connects through the same "forgotten" expansion port. The device is based on the Yamaha YMF288 sound chip and adds new audio capabilities to the original NES.

The module supports several audio channels, including FM channels, rhythm channels with sampled drum sounds, and stereo.

Features of EPSM:

• three FM sound channels;

• six rhythm channels with stereo support;

• support for original Famicom games with expanded audio, such as PowerPak and EverDrive N8.

EPSM uses a 3.5 mm stereo jack for audio output. The system disables the built-in NES RCA/AV outputs when the original 15-pin connector at the bottom of the console is engaged. Here is the project author's GitHub.

Modern interfaces for NES

Another project, ENIO, expands the capabilities of the NES. A modern interface for data input-output is added, so the old console can be used in a new way. For example, connecting to the internet or adding additional modules to improve sound and graphics.

ENIO is based on the PIC32 chip. The microchip manages data transfer between the NES and external devices. Accordingly, the following are added:

• USB (e.g., for connecting keyboards);

• Ethernet (for network functions);

• microSD (for loading games and storing data).

NES upgrade in 2024: NES Hub

In 2024, a new module for connecting to the NES port was announced. It was created by DIY enthusiast RetroTime, and to date, it is the most versatile accessory for the NES expansion port. It is called NES Hub and is only compatible with the NES-001 console version.

What is this module and what can it do? In short, it is a printed circuit board with a lot of functions. NES Hub connects directly to the NES expansion port and provides:

• connecting four controllers via Bluetooth (an alternative to the original NES Four Score accessory, which is now hard to find);

• the ability to connect a SNES controller;

• experimental support for Famicom peripherals (a Japanese game console released several years before the NES);

• new audio capabilities — additional audio features are enabled in some Famicom games.

Probably, NES Hub will support third-party accessories and modules in the future — for example, the currently developing Famicom Disk System drive emulator called FDSKey Drive Emulator. It is being created by Muramasa Entertainment specialists.

RetroTime already has several working prototypes, and the enthusiast plans to send them to beta testers before announcing the module's readiness and making the accessory available for purchase (most likely through 8bitmods and several other niche stores). The device will cost 57 US dollars. Decent, but enthusiasts usually don't skimp on interesting additions for their consoles.

If you know of any other developments, tell us about them in the comments. Not only for NES, but also for other consoles, because there were unused ports in them too. An example is the PS Vita with its proprietary connector.