The concept of cluster system

1. Movement on a channel A wireless unit is said to be active on a channel when it can respond to messages sent to it, or when it is transmitting, or when it is in between these two states. It should be noted that a wireless unit is active as long as it can receive on a designated traffic channel. On a control channel, a wireless unit can only be active when it receives a codeword containing an appropriate system identification code.
2. Addresses and address codewords are used to identify a unit or a group of units within a system. Usually an address contains two sections, namely a prefix and an identification code. An address codeword refers to a channel codeword that meets standard requirements and can identify the nature of a message. Usually the first bit in an address codeword is "1", and the address codeword is always the first codeword in any message.
3. A base station refers to a whole consisting of a transmitter and a receiver operated by a trunking system controller at a certain location.
4. A call refers to a complete message exchange between two or more parties, which includes one or more business transactions and may include direct user-to-user communication on a traffic channel. <1>. A same-prefix call refers to a call with the same address prefix for the calling and called parties. Same prefix calls use the short addressing process. <2>. Different prefix calls refer to calls with the same prefix for the calling and called addresses. Different prefix calls require the use of the extended addressing process.
5. Control channels are used to transmit forward and reverse channels of messages. These messages must comply with the standard and their main purpose is to enable the trunking system controller to control the wireless unit.
6. Calling unit refers to a wireless unit or wired unit that requests a call. The calling unit maintains this identity during a call, and this convention is always used in messages related to that specific call regardless of where the message originates.
7. Data codeword refers to a channel codeword that complies with the standard, usually with the first bit being "0". The data codeword is associated with the address codeword and serves as a supplement to the address codeword message.
8. Transfer refers to a process whereby one party can request that a call to a specific address be redirected to another alternative target. Typically, the alternative target can be a wireless or wired unit, a unit group, a PABX extension, or a PSTN number.
9. Random connection attempt refers to a method by which the wireless unit sends an unsolicited message to the trunking system controller on the control channel. If the wireless unit does not receive a response message within the specified waiting time, this method requires the wireless unit to repeat the random connection message; if no appropriate response is received, it is also required to repeat the transmission further until the specified number of repeated transmissions is reached. Generally, the random connection attempt of the trunking system standard refers to the start of service processing until a suitable response is received or the timing limit is reached.
10. The requesting unit refers to the wireless unit or wired unit that initiates the service processing. The service processing can be between the trunking system controller or between another unit.
11. The requested unit refers to a unit or a group of units participating in the service processing. The service processing is initiated by the trunking system controller or another unit.
12. The reverse channel refers to the wireless carrier in the transmission direction from the wireless unit to the base station.
13. Short data refers to a process that allows data messages to be exchanged between communication objects (including units or users) or between communication objects and trunking system controllers, but a data message does not exceed 4 data code words.
14. Abbreviated PSTN target After pre-agreed between the system operator and the calling unit user, the called PSTN party can be represented by a special identification code instead of a complete number.
15. Special Identifiers Identifiers with special purposes are called special identifiers. In MPT1327 signaling, the decimal value of special identifiers is greater than 8100. Generally, trunking systems will reserve certain special identifiers for system operators to use. Special identifiers cannot be used with prefixes to form addresses.
16. System identifiers A number that uniquely identifies a system. In MPT1327 signaling, the system identifier is 15 bits. Within the system, the system identifier is usually sent on the forward control channel.
17. Trunk system controller TSC refers to the central control intelligent unit that enables the trunking system to achieve the functions specified by the standard. Generally, the trunking system controller can control one or more base stations and can be placed together with the base station or separately. 18. Forward channel refers to the wireless carrier
from the base station to the wireless unit.
19. Group call refers to a call when the group address is the called party, which can provide communication between more than two units. In a group call, the caller can choose the normal mode, that is, a call in which all communicating parties can speak; or the broadcast mode, that is, a call in which only the caller can speak. An identifier with a special purpose is called a special identifier. In MPT1327 signaling, the decimal value of a special identifier is greater than 8100. Generally, a trunking system will reserve certain special identifiers for system operators to use. Special identifiers cannot be used with prefixes to form addresses.