In the past, many power switches were installed in operating rooms; general lighting switches, shadowless lamp switches, hands-free telephones, etc. were all installed separately, which was both messy and hard to locate. Now this has gradually developed into multi-function control concentrated on a single control panel, with switches for, for example, the air conditioner, shadowless lamp, operating table power supply, lighting, film viewer, call system, timer, network terminal, temperature and humidity display and adjustment, etc. integrated together. Figure 6.19 shows the information panel.