The A-155's functions can be expanded a lot by the A-154 Sequencer Controller, as it's an entire control unit with step number limitation, voltage controllable clock generator, variable gate lenght and a number of playback modes.
control inputs: start, stop, clock, reset
3x trigger output, 1x gate output
per CV row: pre output, post output, S&H control input, glide control input
eight external CV/audio inputs for the 2nd sequencer row
3U Euroack Module, 50HP wide, 40mm deep
current draw: 100mA