SONAR DIRECT and SONO DIRECT provide sonar operator (CH124A) with the capability to listen only and directly to sonar or sonobuoy signals. This capability is controlled by a six-position rotary knob on the sonobuoy receiver control panel (Figure 1-12-13), which allows for selection of NORMAL ICS, SONAR DIRECT or SONO DIRECT on any of the four sonobuoy receivers. This feature is disabled by selecting CALL on any ICS master control panel or by depressing switch marked “SONAR CALL” on either collective stick.