The Read In Module format is relatively simple, and probably the easier to implement. Basically, a 12-bit address and 12-bit instruction are split up into four 6-bit words. Channel 8 punches indicate leader or rubout (erased instructions), and channel 7 punches indicate the start of an address-instruction pair.
jnowaczek
commented
2 years ago 
The Read In Module format is relatively simple, and probably the easier to implement. Basically, a 12-bit address and 12-bit instruction are split up into four 6-bit words. Channel 8 punches indicate leader or rubout (erased instructions), and channel 7 punches indicate the start of an address-instruction pair.
See pages Intro-13 through Intro-14: http://bitsavers.trailing-edge.com/pdf/dec/pdp8/software/DEC-08-NGCC-D_PaperTapeSW.pdf