AbstractsIn our hospital, two buildings are separated by public road and was communicated each other using 2 Mbps public cable network. Recently inter-building communication with 100 Mbps infrared has been established for PACS. Gigabit network has been established in the main building. To evaluate usefulness of infrared communication, actual data transfer rate was checked. When 2 Mbps public cable was used, actual data transfer rate using 32 Mbytes text file was 193.9 Mbps. After infrared communication was established, effective network speed between two link heads of infrared was 45 Mbps. Actual data transfer rate with 32 Mbytes text file was 4.98 Mbps. Average transfer rates was also checked each 10 times using compressed medical images of each modalities from CR (4 Mbytes), ultrasound (200 Kbytes), CT (250 Kbytes), MRI (77.6 Kbytes) and fluoroscopy (1 Mbytes), and using a raw data of CR (28 Mbytes). Total average transfer rate was 4.91 Mbps. To compare data transfer rate in the separated building with them in the main building, the rate with a 14 Mbytes CR was checked 10 times at the each building. Average data transfer rate was 6.93 Mbps in the main building and 4.05 Mbps in the separated building. In conclusion, when two hospital buildings are separated, an infrared networking can be replaced for fiber-optic cable networking in PACS environment.