The digital control lines and desirable 'onoff'
controls are routed through a common unit
called the 'multiplexer'. The multiplexer connects
individual control lines in sets of 16 from
each controllable device to the control console
controls (digiswitches) or to the common 16 line
computer data bus. Associated with each digiswitch
or set of controls is a remote-local toggle
switch. In the local switch position, the
multiplexer connects the device to the control
console. In the remote switch position, an external
control signal can connect each device,
one at a time, to the computer data bus.