According to the different structure, it is divided into full utilization harness, partial utilization harness and link system; According to the different service modes, it is divided into loss harness and waiting harness (see random service system); According to the number of load sources of the service, it is divided into unlimited load source harness and limited load source harness.
In telecommunication systems, most of the equipment directly used for communication between users is an unlimited load source loss system full utilization link system, while the equipment used to control the connection process of communication equipment is mostly an unlimited load source waiting system full utilization system. When the number of load sources is not very large relative to the capacity of the wiring harness, a full utilization system or partial utilization system with limited load sources is generally used.
According to the call behavior of the load source, that is, whether a new call attempt is made after the user calls fail, the harness can be divided into repeat call system and non-repeat call system. The actual communication system has repeated calls, and the non-recurring call system is an approximation of the repeated call system.
1) Full utilization harness. Any service device (trunk or machine key) in the harness is called a full-utilization harness if it can be used by any load source in the load source group it serves.
The show shows a fully utilized harness composed of 100 first preselectors (load source groups) of a stepper switch, and 10 lines of its line arc are multiplexed to 10 first selectors (service devices are machine keys). Any service device in the circle (first selector) can be used by any load source (first preselector) in the load source group (100 first preselectors) it serves.
2) Partial utilization harness. If any load source in a load source group can use only a subset of the service devices in the harness, such a harness is called a partial utilization harness. The partial utilization degree harness divides the load source group into several subgroups, and the product compound is carried out between the outlets of the load group, which can be described by the example shown in the figure below.
The 100 load sources (the first preselector in the stepwise switch) are divided into two load source groups, the 1st and 2nd step lines of the first group correspond to the complex connection to the first selector 1 and 2, the 1st and 2nd step exits of the second group correspond to the complex connection to the first selector 11 and 12, and the 3~10 outlets of the two groups all correspond to the first selection group 3~10. It can be seen from the figure that the first selector 1 and 2 (service equipment 1, 2) can only be used by the first group load source, and the first selector 11 and 12 can only be used by the second subgroup load source. 3~10 of the first selection group can be used for the entire load source group (100 first top selectors).
The traffic load capacity of partial utilization harnesses is lower than that of full utilization harnesses under the same harness capacity. Its call load capacity or call loss rate is related to utilization and sub-product reconnection method. Under the condition that the harness capacity and call loss rate are the same, a good sub-product compound structure can improve the load capacity of the harness. The greater the utilization, the closer the efficiency of the harness is to the full utilization harness.
