The transmitter is designed to send a full set of 70 unique coded underwater acoustic commands. It contains a programmable code generator, a high powered audio amplifier and regulated power supply.

The transponder interrogator provides a signal to interrogate the acoustic transponder instrument used with the 1100E. The standard interrogate frequency is 12 KHz, with other frequencies available. The interrogator also provides the start signal for the digital range indicator. This feature allows the user to determine the slant range from the command unit to the underwater transponder. The transpond pulse width selector permits the user to select the optimum pulse width depending upon the range to the transponder.

The receiver is used to detect and indicate receipt of the transponder reply signals and the confirmation of pinger signals. It is a high gain receiver equipped with independent manual gain control, volume control, meter indication of relative signal strength and headphone jack. The receiver is normally tuned to a receive frequency of 8 KHz. Other reply frequencies are available and the acoustic receiver can be provided with multiple frequency selection. A logic level is used to enable the user to determine slant range of the underwater transponder.

The system uses a sequential tone coding technique which is a highly secure coding scheme making accidental or false triggering of the command receiver virtually impossible. The individual codes are made up of four out of a possible eight frequencies which are selected on the front panel.

The 1120 Command Transducer is supplied with 30 meters of cable. It is an omnidirectional transducer, measuring 12 inches in circumference, 8 inches in height (including gland), and 4 inches in diameter.

The 1100E is the Surface Command Control Unit for several InterOcean acoustic products.