This page is a quick reference for readers working through the radio, private mobile communications, and network PTT guide. Definitions follow common engineering and industry usage. Always confirm concrete parameters against local regulations and formal standards.

Calling and operation

English Chinese Notes
PTT 一键通 / 按键发话 Push-to-Talk: press to speak, release to listen; a typical half-duplex interaction model.
Half-duplex 半双工 Communication in only one direction at a time; the dominant operating mode for radios.
Full-duplex 全双工 Communication in both directions at the same time; common in telephony and some data links.
Simplex 单工 / 直通 Transmit and receive alternately on the same frequency, without a repeater.
Duplex 双工 Transmit and receive use different frequencies, or time division, and may go through a repeater.

Networking and coverage

English Chinese Notes
Repeater 中继台 Retransmits signals from a high site to expand coverage; often uses duplex frequencies.
Trunking 集群 Multiple users share a pool of channels that the system assigns dynamically to improve spectrum efficiency.
RoIP 互联网中继无线电 Bridges the RF side into an IP network.
PoC 公网对讲 / 宽带对讲 A PTT service carried over a cellular data network.
MCPTT 关键任务一键通 A 3GPP-defined PTT service in the LTE and 5G framework.

Modulation and analog characteristics

English Chinese Notes
FM 调频 A common analog radio modulation method with a mature trade-off between audio quality and interference resistance.
CTCSS 连续音频静噪 / 亚音 A continuous low-frequency tone used for grouping and squelch control on the same channel.
DCS 数字亚音 One form of digital squelch or selective-calling code.

Digital radio systems (common private-network standards)

English Chinese Notes
DMR 数字移动无线电 An ETSI standards family with Tier I/II/III modes; widely used in commercial radio systems.
dPMR 数字 PMR An ETSI narrowband FDMA system often seen in Europe for license-free or low-power use cases.
NXDN — One FDMA digital private-radio system promoted through vendor ecosystems.
P25 项目 25 A family of North American public-safety digital trunked-radio standards.
TETRA 地面集群无线电 A standard widely used in Europe for public safety and transportation private networks.
D-STAR — A digital mode common in amateur radio rather than commercial private-network deployments.

Internet and real-time communications (common in network PTT)

English Chinese Notes
WebRTC 网页实时通信 A common browser and app stack for real-time audio/video, including DTLS-SRTP and related components.
SFU 选择性转发单元 A server that forwards multiple media streams; commonly used for multi-party rooms.
TURN 穿透中继 Helps media flow through NAT environments; often used together with STUN.
WSS 安全 WebSocket Often used for signaling and presence.

Regulation and device categories (general concepts)

English Chinese Notes
FRS 家庭无线电业务 A U.S. license-free personal radio service with rules that depend on the current regulation version.
GMRS 通用移动无线电业务 A U.S. licensed personal or family radio service with higher permitted power.
PMR446 — A license-free personal radio band used in many European countries, subject to local rules.
ISM 工业科学医疗频段 A category of frequency bands used by some devices; it does not mean a band is dedicated to radio communications.

Further reading

References (conceptual level)

  1. ETSI public standards catalog for DMR, dPMR, TETRA, and related systems: searchable at ETSI.
  2. ITU-R recommendations for radio regulations and service allocation: see ITU.
  3. 3GPP TS 23.179 and related MCPTT specifications, available through 3GPP accounts or third-party summaries.

This page does not constitute a legal or certification interpretation. Deployment and licensing should follow the rules of the local radio authority.