Alternative term: Semi-duplex
The operation of a circuit designed for duplex operation, but which, on account of the nature of the terminal equipment, can be operated in one direction only at a time.
Reference: I.E.C. (modified)
Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)
Celsius (previously Centigrade)
International Association of Marine Aids to Navigation and Lighthouse Authorities - AISM