A hospital nurse call intercom system design (1)

O introduction

Hospital nurse call system is a modern hospital information system, an important part of modern management, you can effectively improve hospital image, strengthen management, guarantee the quality of service.

How to use advanced information technologies for hospital services to a greater extent to improve the quality of service in hospitals, the hospital Informationization construction of an important starting point. This article is designed for the call system, dramatically reducing health care personnel's labor intensity, improves hospital efficiency and service levels, and enhance the competitiveness of the hospital, saving the cost of management, enabling organizations to manage more smoothly.

1 DTMF calling intercom system working principle sketch map of the entire system as shown in Figure 1.

System of the host and extension are single-chip control, host through single-bus and all beds are connected with call intercom functionality. Extension call host, the receiver will extension to DTMF, signal encoded to a 4-bit binary code into the SCM, the host through the decoder receives extension and decoding, control of ringing circuit, LED display and LEDs indicate for sound and light tips, phone can call after the off-hook; host call ext, ext receive host dialed, the number and their inherent in numbers, if the numbers are the same, the receiving phone calls. This system of corridor display can display call beds number, the number of the current call, the call care level, no call displays the real time.

2 DTMF signal describes dual tone multi-frequency transmissions (Dual Tone Multi-Frequency, DTMF) is a new dial-up information in transmission mode, it uses a combination of the two audio to a dial-up key to encode audio, two of which are from different frequency group: low-frequency Group (697 ~ 941 Hz) and high frequency Group (1 633 209 ~ 1 Hz), the frequency of each group consists of 4 different frequencies, which constitute 16 combination represents O ~ 9, *, #, A, B, C and D keys, as shown in table 1.

3 system hardware design

This call intercom system in the body can be divided into three areas, namely the medical personnel on duty, corridors and rooms.

Host, telephone and the display and indicates that the screen is installed in the staff room, corridor has LED digital tube, the extension is installed in the wards. System block diagram shown in Figure 2.

3.1 system working principle

Host is the core of the entire system on the one hand, it is responsible for the extension and the telephone number of the receiving and sending, on the other hand control extension plugged with telephones and fracture, according to the patient's condition, the set of special care, level 1, level 2, level three nursing bed and time display control, level and call instructions, picking the on-hook detection circuit and screen display.