Which of the following is included in packet radio transmissions?
The correct answer is D: All these choices are correct. Packet radio transmissions include a checksum for error detection, a header with the destination call sign, and automatic repeat request (ARQ) in case of error. Packet radio uses the AX.25 protocol, which includes these features for reliable data transmission. The checksum detects errors, the header routes packets to the correct destination, and ARQ requests retransmission if errors are detected. For amateur radio operators, understanding packet radio features helps when using packet systems and explains why packet radio is reliable for data communications.
Exam Tip
Packet radio includes all: checksum, header, ARQ. When all listed features are part of packet radio, 'all of the above' is usually the answer. AX.25 protocol includes error detection, routing, and retransmission.
Memory Aid
"Packet radio includes all: checksum, header, ARQ. Think 'P'acket 'R'adio = 'P'rovides 'R'eliability. Error detection (checksum), routing (header), and retransmission (ARQ) for reliable data transmission."
Real-World Application
You send a packet radio message. The packet includes: (1) A header with your call sign (source) and the destination call sign, (2) A checksum that allows the receiving station to verify the data is correct, and (3) If an error is detected, ARQ automatically requests retransmission. These features make packet radio reliable for data communications.
Key Concepts
Why Other Options Are Wrong
Option A (Checksum): While correct, this is incomplete. Packet radio also includes headers and ARQ.
Option B (Header with call sign): While correct, this is incomplete. Packet radio also includes checksums and ARQ.
Option C (ARQ): While correct, this is incomplete. Packet radio also includes checksums and headers.
题目解析
The correct answer is D: All these choices are correct. Packet radio transmissions include a checksum for error detection, a header with the destination call sign, and automatic repeat request (ARQ) in case of error. Packet radio uses the AX.25 protocol, which includes these features for reliable data transmission. The checksum detects errors, the header routes packets to the correct destination, and ARQ requests retransmission if errors are detected. For amateur radio operators, understanding packet radio features helps when using packet systems and explains why packet radio is reliable for data communications.
考试技巧
Packet radio includes all: checksum, header, ARQ. When all listed features are part of packet radio, 'all of the above' is usually the answer. AX.25 protocol includes error detection, routing, and retransmission.
记忆口诀
Packet radio includes all: checksum, header, ARQ. Think 'P'acket 'R'adio = 'P'rovides 'R'eliability. Error detection (checksum), routing (header), and retransmission (ARQ) for reliable data transmission.
实际应用示例
You send a packet radio message. The packet includes: (1) A header with your call sign (source) and the destination call sign, (2) A checksum that allows the receiving station to verify the data is correct, and (3) If an error is detected, ARQ automatically requests retransmission. These features make packet radio reliable for data communications.
错误选项分析
Option A (Checksum): While correct, this is incomplete. Packet radio also includes headers and ARQ. Option B (Header with call sign): While correct, this is incomplete. Packet radio also includes checksums and ARQ. Option C (ARQ): While correct, this is incomplete. Packet radio also includes checksums and headers.
知识点
Packet radio, AX.25 protocol, Error detection, ARQ
Verified Content
Question from official FCC Technician Class question pool. Explanation reviewed by licensed amateur radio operators.