*This model supports selective signaling between up to 16 Call Signal Stations, and common audio for a maximum of ~20 endpoints (headset/chestsets and/or handsets) connected either to jackboxes or directly to Call Signal Stations.
*A side-mounted hand crank is used to generate an audible signal to a far-end Call Signal Station, as selected by the front panel 16-position rotary switch.
*A front-panel ‘Howler’ (speaker) signals Incoming calls from another Call Signal Station on the same circuit, whenever the far-end Call Signal Station hand crank is operated and the appropriate station number is selected.
*Modifications of the basic Type IC/D call signal station are available to meet special design requirements.
*All Call Signal Stations are manufactured and approved to the latest military specification.

*This unit allows an operator to participate in the conversation on any one of up to 16 separate circuits.
*Watertight 16-position rotary switch, equipped with a case-mounted sound powered telephone jack.
*Internal switch contacts are silver plated for long life and good conductivity.
*The dial on the rotary selector is backlighted for night time use.

*Designed to reproduce voice signals so that the message will be clear and understandable through high ambient noise levels such as gun positions and machinery spaces.
*Volume is adjustable at the front panel. Audio levels can be reduced by 24 dB in five equal 6 dB steps.
* Amplifier supplies amplified signals to speakers and headsets at the associated position. Signals from the position to the command post are transmitted directly at the sound powered telephone level.
*Direct communication at the sound powered telephone level (no amplification) is maintained when the amplifier is not operating, the press-to-talk switch of a local sound powered telephone headset is closed, power is interrupted, a sensitive switching circuit fails, or when the amplifier is removed from its enclosure.
*Uses a plug-in circuit card for easy repair / replacement.

It is used for speaking and listening in Sound Powered Phone System. Also available as duals and quads jackbox.
Features
*Watertight Jackbox Type G15A, provides a single H27A sound powered telephone jack mounted in a brass enclosure.
*For use with sound-powered equipment equipped with H39A plugs.
*The jack is designed to prevent short circuits from water entry into the enclosure when the cap is not covering the jack.
*A screw-on watertight cover for each jack is provided with each unit, and is secured to the front panel of the unit with a 6-inch lanyard.

SOUND POWERED TELEPHONE SYSTEMS
The Navy’s time-tested and proven emergency shipboard communications system, requires no external power to operate. In cases where electrical power is unavailable to other communication systems, Sound Powered Telephone (SPT) will continue to operate, and is therefore the primary means of communication during damage control evolutions or when close-quarter ships movements will not tolerate a loss of communications. The equipment in this category covers a wide number of applications, and is time-tested to perform under pressure.
Head-Chest Set is used for speaking and listening in Sound Powered Phone System.

Features
*Military-grade Sound Powered Telephone head – chest set.
*Weatherproof, designed for typical shipboard environments.
*Adjustable, boom-mounted microphone attaches to a chest plate for situations where the operator must have both hands free.
*A pair of over the ear receivers (speakers) attach to a cushioned headband. The earcups are padded and cushioned for comfort.
*Microphone is equipped with a PTT switch.
*Optional battery-powered microphone amplifier P/N 62077-200 boosts the voice level coming from an individual station, making it easier for other stations to hear.
*Supplied with a 20 foot cord terminated in a H39A plug, compatible with all devices equipped with an H27A jack, such as jackboxes, rotary selector switches, and select call signal stations.