i guess the same goes for mpc1000 - only in/out there, can't find anything mentioned of thru...
someone able to do a small test quickly

?
edit. ok i found this
"
The 'Soft thru' field determines how to output the incoming MIDI signal. The following choices are available:
Off - The MPC500 will not output the incoming MIDI signal.
On - The MPC500 will output the incoming MIDI data to the MIDI OUT
on the channel it was received.
As track - The MPC500 refers to the MIDI channel setting of the sequence's
track. The channel information of the incoming MIDI signal will be
set to the MIDI channel of the currently selected track.
"
something like thru... but how about passing sync then?