 fiber-optic modems is for use within a building, most such devices permit sup- port for transmission on a university or other campus or even within an industrial park. For example, the TC1540 supports a transmission distance of up to 3 km on multimode fiber at a wavelength of 850 nm and up to 4 km when a wavelength of 1310 nm is used. When single- mode fiber is used at 1310 nm, a transmission distance of 24 km becomes possible. Because the optical loss budget, including connectors and fiber loss, determines whether it is possible to reach a predefined range, it is important to check the connectors as well as consider the total loss of the link. Concerning the latter, Table 8.2 indicates the approximate loss per kilometer that you can use for four different types of optical cable. Chapter Eight TABLE 8.2 Fiber Link Loss Values Multimode, 850 nm 3 dB/km on 62.5/125-um cable Multimode, 1310 nm 2 dB/km on 62.5/125-um cable Single-mode, 1310 nm 0.5 dB/km on 9/125-um cable Single-mode, 1550 nm 0.4 dB/km on 9/125-um cable In examining Table 8.2, you need to consider the loss on different fiber in conjunction with transmitter launch power and receiver sensitivity. For example, the TC1540 has a typical launch power of -20 dBm for mul- timode fiber at both wavelengths (850 and 1310 nm) as well as for inser- tion into single-mode fiber at a wavelength of 1310 nm. The sensitivity of the TC1540 is -36 dBm for both types of fiber at all three wavelengths. To facilitate the optical modem selection process, Figure 8.3 includes a list of key device selection features in the left column. The first col- umn to the right of the "Feature" column is labeled "Requirements" and represents a location where you can define your specific requirements for a fiber-optic modem features. The two columns to the right of the "Requirements" column enable you to compare two vendor products against your specific requirements. Of course, you can duplicate this table to compare products from more than two vendors. Fiber-Optic Multiplexers A second fi