DF11 Communications Line Adapter
The DF11 Communications Line Adapter performs two functions for serial line communication links on PDP-11 computers: i) converts from TTL signal levels to the voltages, etc needed by a given serial line standard, and ii) produces the physical connector needed for that standard.
A DF11 usually involves two single-width cards, one holding the circuitry needed, and the other providing, sometimes with a cable plugged into a Berg connector, the interface connector. At least one dual-width adapter existed, though.
DF11 models include: