1771-DB Module Call 6/7 Variables

I am racking my memory to understand what happens when a Call 6 (BTW) happens and Call 7 (BTR) .. the manual doesnt handle these call descriptions very well, unless I am missing something.
when you do a Call 6 where does the DB put the data? the manual indicates that it is a memory location like 7800H but the DB program I am working with simply does this:
610 CALL 6
620 PUSH 1 : CALL 11 : POP V
630 CALL 7
I cant remember if the '1' is the number 1 or an index into the BTW data, and the 'V' is an index into the BTR data or it is simply a variable.
I seem to be lost in space:) it has been 30 years since I worked with this module:) seems my memory is a bit fuzzy:) any help and guidance is appreciated