M2 : Also called PHI2 (φ2) in official docs (however, see the CPU M2 and CLK description for additional details).

It is only available on 72-pin connectors, and its speed varies between NTSC (21MHz) and PAL (27MHz) machines.

SYSTEM CLK : Main oscillator frequency output.

+5V : 5V Power supply from the main voltage regulator.

So an input is a signal driven by the cartridge to the console, and an output is a signal driven by the console to the cartridge connector. Unless otherwise specified, these signals are from the console's viewpoint. Most cartridge PCBs made by Nintendo are numbered the same way as indicated in these diagrams.The NES and Famicom connectors have a similar arrangement the connector on the NES is mostly a mirror image of the Famicom's.Active-Low signals are indicated by a / (slash) symbol.For the NES: most chips and components appear on the label side of the PCB in NES cartridges.(Nintendo boards follow this convention, but third party boards vary.) For the Famicom: most chips and components appear on the opposite side of the PCB from the label in Famicom cartridges.Typical female board edge connectors are not compatible. The pitch, or pin spacing, of this connector is 2.5 0mm. Pins 36–01 are on the label side of the cartridge, left to right. On a front-loader, pins 01–36 are the top side of the connector. This diagram represents a top-down view looking directly into the connector. Pinout of 72-pin NES consoles and cartridges The pitch, or pin spacing, of this connector is 2.5 4mm.

Pins 01–30 are on the label side of the cartridge, left to right. Pinout of 60-pin Famicom consoles and cartridges

2 Pinout of 72-pin NES consoles and cartridges.

1 Pinout of 60-pin Famicom consoles and cartridges.

Famicom with slot for card games