I wrote this elsewhere, but it should be its own thread.
DEC picked up TENEX and made TOPS-20 from that. There was a DEC
product called TOPS-20AN which retained the ARPANET code. So far, no
one has tried running that on an emulator.
Here are some resources: tapes, documentation, etc.
DEC made their own IMP interface called AN10 or AN20. This would have to be added to the KL10 emulator(s).