pdp BASIC-11 query

I'm posting this on behalf of someone not on the list. I didn't want to just open them up to tons of replies, so figured I'd just post it for him and relay any responses back. Can anyone solve his issue? He wrote.. I'm trying to get some code that was written in 1977 working again. I've gotten a PDP-11 emulator working but the version of BASIC that is on it doesn't know the 'FILE #1="DNG1' command. I've been digging through BASIC manuals for BASIC-11 and BASIC-Plus but so far they either don't have an file reading or their file reading commands don't match that syntax. Googling has led me to a few other versions of BASIC that were on the PDP-11 but I can't find manuals for them. Can you point me in the right direction? (The full code is here; https://d2sx9mrt4zumaq.cloudfront.net/wp-content/uploads/2014/04/DND1_Comple te.pdf)