This page was last modified 03:22, 20 November 2021 by Mars2000you. Based on work by Gdx.

The J3125 chip was produced by Yamaha for ASCII in 1986. It is called MSX-Interface.

It is an asynchronous serial communication interface that can by used for general purpose network.

This chip includes a frequency divider circuit for communication rate generation, an interface for magnetic tape, a large-capacity data buffer for transmission / reception, timer, etc.

According some sources the J3125 chip would be compatible with the YM3523/YM3802 chip from Yamaha (used in the MIDI interface of the non-MSX Sharp X68000 computer, in the network interface of the Russian MSX2 Yamaha YIS-503IIIR and Yamaha YIS-805/128R2 machines). Only the FIFO size would be different.

I/O ports reserved to access this chip are C8h~CCh.

MSX-Interface is an optional function of the MSX standard which never seems to have been used.