High Quality Content by WIKIPEDIA articles! The Yamaha MU5 was an early sound module, commonly used when computers had the Intel 80386 processor, in which a computer could send MIDI commands to the MU5, acting as an external sound generation device. THe MU5 ran on six AA batteries, or on an external DC supply. THe display showed 16 bargraphs, one for each MIDI channel. REleased in 1994. GEneral MIDI voices only, no effects. PLastic case (7" x 4" x 1.5" (19 x 10 x 3.5 cm) with LCD display. TO-Host serial RS232 38.4K baud input as well as MIDI. RS232 from the PC to the MU5 using the to-host cable is retransmitted as MIDI by the MU5. MIDI Into the MU5 is converted to RS232 38.4Kbaud and sent out the to-host cable to the PC. USing a computer operating system's available serial port routines, the MU5 proves to be an inexpensive and simple means to developing hobbyist MIDI control software.