I recall that system had many boards, the whole "CPU" box was external to the monitor (and in the earliest versions, the power supply was also a large external box). I can't really fathom creating a BASIC out of raw TTL, or maybe I'm misunderstanding the approach.
You build a processor with some TTL, and then implement a BASIC on that microprocessor. There is always this intermediate step, no machine executes BASIC directly in TTL.
Look here for an example of a processor (Datapoint 2200) in TTL : https://bitsavers.org/pdf/datapoint/2200/jdreesen_shematics/DP2200_mb.pdf Jos
