Obviously, communication is vital for police officers. Since they are required to communicate across wide areas, use a massive number of terminals, and coordinate frequently across departments, a secure, reliable and efficient voice communication system is essential for every critical mission.


As a voice-based wireless communication network for dispatching, the 350M wireless trunking system for public security is indispensable for missions like dispatching, disaster relief, rescue, incident response, traffic management and police’s routine patrols.

The system can handle a massive number of voice calls, cross-department and cross-region calls, deliver wide signal coverage, and support roaming. Its networking model involves three categories: single base station in a single region, multiple base stations in a single region, and multiple base stations in multiple regions. This model is geared to satisfy the needs of provincial, municipal, and county-level public security functions.

  1. Single base station in a single region – As the basic networking pattern, the model builds on a modular design to deliver wide regional coverage. In a geographically flat region, the coverage radius of a portable radio can reach around 15 kilometers. The 4-channel trunking system can support around 200 terminals on the network and the number of channels varies with the user base. As the major networking model for use in counties and rural areas, this network provides a full range of standard trunking capabilities, such as individual, group and emergency calls and two-way radio calls.
  2. Multiple base stations in a single region
  3. Multiple base stations in multiple regions


  1. A comprehensive array of dispatching functions – The trunking system supports a diversity of calling modes – individual and group calls, inclusive calls, temporary grouping, emergency calls, and interconnection & interoperation between wired and wireless communication networks.
  2. Flexible user numbering rules – The trunking system is compatible with MPT-1343 and CPSX numbering plans.
  3. Full scalability – The system supports a wide diversity of expansion modules, such as real-time recording subsystem, visualized dispatching subsystem, GPS subsystem, and 3-in-1 access subsystem. These modules combine to increase the system’s scalability in terms of functionality and performance.
  4. Smooth inter-network switchover – Calls from a mobile station to another can be smoothly switched over to another network without a second login or voice interruption. The switchover takes less than 100ms, undetectable by the human ear.
  5. IP networking – Voice packets routed are IP voice packets. The softswitch reduces voice distortion and gives flexibility to voice packet transmission over IP LANs.
  6. Fully automatic user roaming – The system automatically allows users to roam between multiple base stations and systems without manual intervention.
  7. Connecting heterogeneous networks – The system can communicate with other MPT-1327 systems in wired and wireless modes. The wired internetworking relies on IP softswitch, while wireless internetworking is implemented by resolving signals on air interfaces of the MPT-1327 system. This removes the need to modify the original MPT-1327 system.
  8. Strong fallback control – The QH-1327 trunking system features a solid multi-level fallback control capability, which meets the requirements of the Chinese Ministry of Public Security for fallback control. Level-1 network faults do not affect the running of level-2 networks, while level-2 network faults have no impact on the running of the trunking system. In turn, faults with trunking control devices do not interfere with base stations. Signaling channels of the QH-1327 trunking system support hot backup through a complete set of devices from control units to channel devices.
  9. High privacy – The trunking system closely detects the access of networked terminals and keeps calls between users in strict confidence. Administrators can remotely kill lost terminals and block their access to the network.
  10. Other features – In addition to standard trunking functions, the solution supports intelligent squelch and SMS-based alarms.


350M trunking system of Guizhou Province, China, incorporates over 80 base stations and more than 340 channels. By employing a range of advanced technologies, such as IP softswitch, fully automatic user roaming, and smooth inter-network switchover, the system enables users to make calls via two-way radios across the province and experience no call drops across base stations.

The following figure shows how Guizhou’s 350M trunking system is networked:

As the extension of “single base station in a single region”, this networking model is designed to cover more far-flung areas. This networking model supports cross-base-station voice calls, two-way radio calls and roaming. Therefore, this solution is ideal for public security departments in large cities to cover diverse areas.


  • QH-1327 trunking system
  • TC-780M trunking two-way radio
  • TC-790M trunking two-way radio for police
  • TC-890GM multi-mode two-way radio for police
  • TM-800U trunking mobile radio

As a multi-level networking structure, this networking model connects trunking systems distributed in multiple cities through a network switching center to form a network that covers a province. IP softswitch is used for a province-wide network. The softswitch host is deployed in the provincial public security department. IP access terminals are located where the 350M trunking system is deployed in the province, cities, and counties. The solution integrates cutting-edge technologies, such as TCP/IP and VoIP, for network-wide interconnection and interoperation. The approach enables users to call and roam across the province with two-way radios.

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