This information comes from the "LINC-8 Users Handbook" which can be found as a section beginning on page 299 of the "Small Computer Handbook", March 1967 edition. Page 347 begins a discussion of the PDP-8 IOTs to control the LINC in the LINC-8: 6141 ICON LINC CONTROL AC8:11: 00 0 to MOTION 01 AC0 to MOTION 02 Search the tape unit indicated by A0 03 Set block transfer mode for the tape 04 Unset block transfer mode 05 Begin writing tape data 06 Stop writing tape data 07 Clear all LINC interrupt flip flops 10 Select the LINC 11 Stop (reset) the LINC 12 Start the LINC execution 13 Delayed LINC restart 14 Clear the Z register 15 Transfer from B to Z 16 Not Used 17 Not Used 6143 IBAC READ LINC B REGISTER The LINC B register is read into the PDP-8 accumulator. 6145 ILES READ LEFT SWITCHES The left switches are read into the PDP-8 accumulator. 6145 INTS READ LINC INTERRUPT STATUS AC00 Tape interrupt flip flop AC01 LINC Console function interrupt flip flop AC02 Execute class interrupt flip flop AC03 Address match interrupt flip flop AC04 Auto-restart delay interrupt flip flop AC05 MTP instruction indicator AC06 OPR instruction indicator AC07 EXC instruction indicator AC08 RUN INT flip flop AC09 Not Used AC10 Mag Tape MOTN flip flop AC11 Mag Tape MOTN flip flop 6151 ICS1 READ LINC CONSOLE SWITCHES AC00 STOP AC01 FILL AC02 FILL STOP AC03 EXAM AC04 STEP EXAM AC05 INST X INST AC06 STEP AC07 RESUME AC08 DO TOG AC09 START RS AC10 START 20 AC11 START 400 6153 ICS2 READ LINC CONSOLE SWITCHES AC00 MARK AC01 AUTO RESTART AC02 I STOP AC03 E STOP AC04 CLEAR AC05 AUTO flip flop AC06 Not Used AC07 Not Used AC08 Not Used AC09 Not Used AC10 Not Used AC11 Not Used 6155 IMBS READ MEMORY BANK SELECTORS AC00 Not Used AC01 Not Used AC02 UMB0 AC03 UMB1 AC04 UMB2 AC05 UMB3 AC06 UMB4 AC07 LMB0 AC08 LMB1 AC09 LMB2 AC10 LMB3 AC11 LMB4 6175 IACF SET LINC INDICATOR FLIP FLOPS AC00 Not Used AC01 Not Used AC02 CLEAR flip flop AC03 INST X INST flip flop AC04 F STOP flip flop AC05 E STOP flip flop AC06 AUTO flip flop AC07 KEY STRUCK flip flop AC08 Not Used AC09 MARK flip flop AC10 Extended tape unit U1 AC11 Extended tape unit U2 6161 IACB SET LINC B REGISTER PDP-8 Accumulator is transferred to LINC B register. 6163 IACS SET LINC S REGISTER PDP-8 Accumulator is transferred to LINC S register and LINC B regiser is cleared. 6165 ISSP SET LINC P REGISTER PDP-8 AC2:11 is transferred to LINC P register. Previous LINC P register replaces B2:11. S register cleared. 6167 IACA SET LINC ACCUMULATOR PDP-8 Accumulator is transferred to LINC B register and LINC Accumulator. 6171 IAAC READ LINC ACCUMULATOR LINC Accumulator is transferred to LINC B register and PDP-8 Accumulator. 6173 IZSA LINC Z TO A LINC Z register to LINC Accumulator. LINC B register is cleared.