The 312B-4 and 312B-5 Station Controls, figure 1, contain a directional coupler and wattmeter, a speaker, a phone patch, and appropriate switching circuitry. The same types of directional coupler and wattmeter, phone patch, and speaker are used in both the 312B-4 and 312B-5. In addition, the 312B-5 contains an auxiliary variable frequency oscillator to provide separate transmit and receive frequencies when used with the KW.VI-2 or KWM-2A Transceivers (see table 3). The wattmeter indicates power levels within the ranges of 0 to 200 or 0 to 2000 watts, forward or reflected. It is accurate over the range of 2 to 30 MHz, but should not be used on higher frequencies. The phone patch includes circuitry which allows VOX phone patch operation. It can also be switched manually if desired. The vfo in the 312B-5 is the same as that used in KWM-2/2A and S-Line equipment. Switching circuits are provided to allow operation of KWM-2/2A Transceivers on different transmit and receive frequencies or transmit-receive operation on :he same frequency using either vfo. Figure 2 shows the location of external connections to the 312B-5. The 312B-4 and 312B-5 are electrically identical except for the absence of vfo connections in the 312B-4.