Wired Calling System Design For The Medical Use On The Local Area

This paper discussed the concrete design and the method of realization on the wired calling system for the medical use on the local area. The hard wares of this system were constituted host and extension. The whole core of this system makes up of the single machine chip MCS-51. The underground program of host always was looking up by making use of multi-machine communication principle of single machine and circle inquiring approach. Phonic signals were transmitted between the host and extension by 1062A,and close and open of relay was controlled by single machine so we can choose an extension. It can make the program by C51 on the software. The system adopt solid hour search a way which saved a hardware resources,to make the system have characteristics as hardware in brief, the procedure adjust to try easily, the function strong etc. The system mainly applies a correspondence in RS485 half double string line agreement which can carry out a long-distance information for leaving to deliver with control ,and adopts 12864 liquid crystal displays which can show sickroom and sickbed number by dynamic state, and make use of the DS1302 clock chip carries out ten thousand calendar functions, and also adopt the using constituted data in common of the 24C02 chips saving system.This paper included four parts. First, actuality of the wired calling system for the medical use on the local area was analyzed, and existent questions of wired calling system for the medical use on the local area in being were summarized. Meanwhile, requirement of design and pre-realization function of this system were presented in allusion to deficiency of existent wired calling system for the medical use on the local area.Secondly, the design plan and the technology indexes of this system were discussed. Main technology indexes included: maximum capacity of host carrying extension was 128; maximum capacity of extension carrying load was 8 sickbeds (extendable terminal); maximum store capacity per unit was 256dB;voltage was 5V; using continue function mode; distance of communication was at most 1200m; maximum current of host was 500mA; maximum current of extension was 100mA;output power of loudspeaker was 350mw.Next, hardware design of the wired calling system on the local area was discussed. The cores of host and extension were 89C51, given actual application environment and production cost of system, and we communicated by using TEA1062A telephone chip, which can realize audio communication between host and extension. Otherwise it can provide some functions such as eliminating noise and auto-gain control.Finally, detail software design of the wired calling system on the local area was discussed. This soft-system were make up of soft of host and soft of extension. The host program included main functions program of host and interrupt function program of host. Host program mainly echoed calling, looking up, and function set up of extension, and looked up, set up and managed extension. The extension program also included main functions program and interrupt function program of extension. Main function of Extension program called host and echoed calling of host. All program were edited using C of single machine.