Buchla 242 Pulse Prog. Question

[R.Fahl]

I've been looking at the pic of the Buchla Programmable Pulser that's on
Kevin Lightner's page and I think I understand how the module works.  It
seems like you can do some type of drum machine style pulses with it (a
proto-schaltwerk?) - each pin in the matrix closes a switch which allows a
pulse to be transmitted to that row's output when the counter reaches that
step.

I see only three outputs, corresponding to rows A, B, and C, but what does
the top row do?

This seems like a clever way to get complex patterns going, triggering EGs
and sequencers rhythmically, but allowing rests.  Seems like it could be
done with the counter circuit of choice.  With modern ICs you could
probably add new features.

R>