Chapter 2, Control and Connector Basics
ALESIS M20 REFERENCE MANUAL 1.06 2-3
2.2 ABOUT THE REAR PANEL
Referring to Fig. 2, the rear panel includes:

2.2A PUNCH FOOTSWITCH

This allows foot-controlled punch in and out. Use a momentary footswitch, either normally-
open or normally-closed (the M20 senses the type on power-up and calibrates itself).

2.2B LOCATE/PLAY OR LRC REMOTE CONTROL JACK

This 1/4” jack accepts a momentary footswitch (normally closed or open) to allow foot-
controlled location functions. It also accepts the LRC remote control (see Chapter 14) for
remote access of transport functions.
Note: If using a normally open footswitch, the footswitch and LRC remote control can be
interchanged, or used simultaneously with a Y-cord, without restarting (powering
down and powering up) the M20. However, if using a normally closed footswitch,
the M20 unit should be restarted after switching from footswitch to remote control
and vice-versa.

2.2C ANALOG INPUTS AND OUTPUTS

18 XLR connectors carry the +4 dBu balanced analog inputs and outputs. There are 9 audio
input and output channels (channels 1 through 8 plus Aux). Channels 1 through 8 inputs and
outputs are also accessible through a multi-pin ELCO connector, which is wired in parallel
with the XLR inputs and outputs. All XLR connectors are wired with pin 2 “hot,” in
accordance with IEC standards.

2.2D TIME CODE IN AND OUT

The time code input and output use balanced XLR connectors for use with SMPTE/EBU
standard time code systems. Time code input allows the M20 to be slaved to an external
device; time code output provides timing reference to an external device.

2.2E WORD CLOCK IN AND OUT

These are BNC connector, TTL-level word clock inputs and outputs. A master word clock
signal, which the M20 can provide, allows synchronizing the audio data stream for all digital
audio devices in a system. If a master word clock signal already exists, the M20 can sync to
it.

2.2F ADAT OPTICAL IN AND OUT

The optical input and output are an industry-standard digital audio interface, pioneered by
Alesis, that carries 8 digital audio channels (with up to 24 bits of resolution) on a single fiber
optic cable. The standard cable is a 1mm diameter plastic fiber with Toslink connectors. One
1-meter cable is provided with the M20; additional cables of different lengths are available
from your dealer. Applications include digitally dubbing from one deck to another,
interfacing with hard disk recording systems and synthesizers, and feeding translators that
change the ADAT optical format to other formats.