La Sesenta y Siete 123, as per the original manual, produces a repetitive sequence of from two to eight programmed control voltages at each of the 3 outputs.

"The Model 123 Sequential Voltage Source, one of the most important modules of the 100 System, produces a repetitive sequence of from two to eight programmed control voltages at each of the three outputs. Its front panel includes a timing pulse input , an output rotary switch, three pairs of control voltage outputs, eight timing pulse outputs, eight red indicator lamps, and three rows of eight control voltage potentiometers.

The timing pulse input usually comes from a model 140 Timing Pulse Generator, but it may also come from a Touch Controlled Voltage Source. The timing pulse determines the switching between a sequence of between two and eight groups of three programmed control voltages. The number of events in the sequence is determined by the output rotary switch. Upon receiving a timing pulse, the unit moves to the next group of programmed control voltages. The switching is sequential, so that when it reaches the end of the sequence it returns to the beginning. The eight red indicator lamps show which group of three associated control voltage potentiometers are currently in control. The potentiometers are arranged in a 3x8 matrix. Each column is associated with a single even, with the corresponding indicator lamps located immediately above. Each row is associated with the same control voltage output jacks: the top row feeds jacks "A", the middle row jacks "B" and the bottom row jacks "C". the eight pulse outputs are energized as the corresponding segments are switched. 

Thus, up to three parameters of a repetitive sequence of up to eight notes may be separately and simultaneously controlled. These parameters may correspond, for example, to pitch, amplitude, and duration."