[sdiy] Kenton Pro 2000 "clock" question

[synth at oldmail.charlielamm.com]

I bought one of these, it has an output called "clock".

Does anyone know of the electrical characteristics of this output?  There
are two modes--positive going and negative going.  I am a bit lazy to plug
in my scope and figure this out, I was hoping someone already knew what
was going on with this signal.  

This clock out signal can be used to interface to drum machines and
sequencers so I assume it's some sort of standard or protocol?

Thanks.... --CL