Like the evolution in word processing, spreadsheets, and accounting, linking computers with keyboards has evolved from a complex process used only by professionals and diehard enthusiasts into something that can be learned quickly by the novice. Now even the casual player can play a song on a digital piano and print out the sheet music, or take interactive lessons, without leaving the house. This is made possible largely due to the Musical Instrument Digital Interface specification, known by its acronym MIDI.
Electronic musical instruments had been around for decades, but were unable to "talk" to each other until 1982 and the introduction of the MIDI specification. Many musicians used two, three, or more synthesizers in their setups, each with a distinctive palette of sounds, to provide the widest possible range of voices. The problem was that the musicians couldn't combine sounds from different synthesizers and control them from a single keyboard, because of differences in the electronic commands to which each synth responded. This ultimately led to a proposal for a common set of commands to which all digital musical instruments could respond.
MIDI is now standard on all digital pianos. While it does allow your instrument to control or be controlled by other instruments, today it's most often used to connect the instrument to a computer. Connecting your instrument to a computer allows you to venture beyond the capacity of even the most capable and feature-packed digital piano.
Connecting two instruments to each other requires two MIDI cables—one for each direction of data transmission between the two devices. Standard MIDI cables use a 5-pin DIN connector, shown here. Since personal computers don't use 5-pin DIN connectors, connecting a keyboard to a computer requires an adapter that has the MIDI-standard DIN connector on one end, and a computer-friendly connector on the other.
In 1995, the USB standard was introduced to reduce the number of different connectors on personal computers. Subsequently, MIDI over USB has emerged as an alternative that replaces two MIDI cables with a single USB link. In addition to being a common connector on personal computers, USB's higher transmission speed increases MIDI's flexibility by allowing MIDI to control 32 channels instead of the 16 specified in the original MIDI standard. USB connectivity is now finding its way into the digital piano. All current digital instruments still have 5-pin DIN connectors for traditional MIDI, but many now sport USB connectors as well. One thing to be aware of is that there are two types of USB connections that can appear on instruments. One, "USB to Device," allows direct connection to a variety of external memory-storage devices. The other, "USB to Host," allows connection to computers. If you plan to use these connections, you need to check the type of USB connections available on the instruments you're considering. Simply stating "USB" in the specifications doesn't tell you the type of USB connectivity provided.
For more information on MIDI and on connecting external memory, see "Digital Piano Basics, Part 2: Beyond the Acoustic Piano" in Acoustic & Digital Piano Buyer.
Introduction to Buying
a Digital Piano