DESCRIPTION: The 236A Test Oscillator is particularly useful for lineup and maintenance of telephone voice and carrier systems when used with the 3555B Transmission Noise Meter (sold separately). The 236A generates sine wave signals from 50Hz to 560kHz at an output level adjustable from +10 dBm to -31 dBm in steps of 10, 1, and 0.1 dBm. The function switch selects a balanced output with impedance of 600 or 900-ohms from 50Hz to 20kHz and 135-ohms from 5kHz to 560kHz. The first position of the function switch, designated DIAL/DC, connects the DC TEST meter to the power supply for checking the battery of the AC power supply. In this position of the function switch, the dial terminals are connected to the output terminals for dial through operation. The function switch also provides a hold position for 600 and 900-ohms output impedances to simulate an off-hook condition. The added path furnishes a shunt for DC but offers high impedance to the oscillator signal.