Advanced Qualification · A-005 Transmitters, modulation and processing · A-005-008-002
Open Systems Interconnection (OSI) model standardizes communications functions as layers within a data communications system. Amateur digital radio systems often follow the OSI model in structure. What is the base layer of the OSI model involving the interconnection of a packet radio TNC to a computer terminal?
- AThe network layer
- BThe transport layer
- CThe physical layer
- DThe link layer
Correct answer: C — The physical layer. From the official ISED question bank, verified word for word.
Why
The physical layer is the correct choice because it handles the actual hardware connections and electrical signals that let a TNC talk to a computer terminal. The full explanation — and one for every question — is in Pro.
Practise this section
Transmitters, modulation and processing is section A-005 of the Advanced exam: Transmitters, modulation and processing: AM, FM, SSB, keying, speech processing, and the numbers behind occupied bandwidth.
Drill A-005 — free, no account