The 1120B Directional Command Transducer is normally used as the shipboard Command Transducer for InterOcean's Model 1100ES Acoustic Command and Control System. The 1120B contains bearing and range measurement transducers. Directional (bearing) information is provided by four internal reference receivers utilizing USBL (Ultra Short Baseline) technology. The output of each bearing transducer is fed to a tuned pre-amplifier that provides 24 dB of gain for the low level output signal. The range transducer output is provided directly, without the need for a pre-amplifier.