The Hewlett-Packard Model 5087A is a narrow-band amplifier capable of receiving up to four different input frequencies on three input channels. It amplifies these frequencies and supplies outputs in any selected combination on a total of 12 output lines. Table 1-4 lists the assembly designation, description, function, where it is used, the corresponding HP part number and its assigned option number. The three input lines are labeled A, B, and C while the 12 outputs lines are labeled 1 through 12. Each input line, as well as the 12 output lines and the power supply voltage, may be monitored by a front-panel meter through a 16-position front-panel switch. All input and output connectors and fuses are mounted on the instrument rear panel. All controls and indicators are mounted on the instrument front panel.