In a communication model where data transmission occurs in both directions, but only in one...
IBM aptitude question, verified with a worked answer. Free to practise - no sign-up.
In a communication model where data transmission occurs in both directions, but only in one direction at a time, the communication system is called:
Show answer & explanation
Answer: B. Half duplex
Half-duplex transmission allows data to flow in both directions, but only one direction at a time—when one device transmits, the other must receive and vice versa. Simplex is one-way only; full duplex allows simultaneous two-way transmission; multiplex is about sharing a single channel among multiple users.
Step-by-step Derivation:
Analyze each transmission mode:
- Simplex: Unidirectional only (e.g., TV broadcast, radio). Data flows one way only.
- Half-duplex: Bidirectional but alternating. Data can go both ways, but not simultaneously (e.g., walkie-talkies, old modems). This matches the question description exactly.
- Full-duplex: Bidirectional and simultaneous. Data flows both ways at the same time (e.g., telephone calls, modern internet).
- Multiplex: A technique to combine multiple signals on one channel, not a transmission direction classification.
The question explicitly states 'both directions, but only in one direction at a time'—this is the definition of half-duplex.