DATIS is a form of ATIS, the Air Traffic Information System that uses digital recording and message playback techniques eliminating the wear and tear problems of mechanical systems and thus increasing the reliability and availability of the service.
 

 The P. A. Communications "DATIS" provides a continuous flow of spoken information by replaying a recorded message.

The message text is recorded by the operator and is retained in a VOICE STORE, when the message is recorded and checked it may be put into service as being the current information.

The DATIS is normally operated from a remote control panel.

Additionally there are local "engineering" controls on the front of the DATIS subrack.

A key operated switch on the DATIS subrack is used to select between the two sets of press buttons.

 

Remote control panel options.

Supplied with one of two alternative styles of switches fitted to sturdy 3 mm aluminium alloy front panels, when a flat surface or table top is the only available place for operation, the 3U type can additionally be fitted into a wedge shaped case, possibly prior to the permanent fitting of these controls flush into an ATC desk

 

 

 

The DATIS has two voice stores, this allows one store to be broadcasting while the other is available for the preparation of the next message. Changeover, when initiated, will occur at the completion of the message currently being transmitted.

Messages are recorded at the remote control using the operator's headset.

The selected store will continue to playback, repeating the message until the operating requirements are changed.

The audio voice signals from the DATIS to the ATIS transmitter are continuously monitored and an alarm is given if the signal fails or drops to a low level.

Audio signals are standard 600 ohm balanced pairs.

One of the two stores is selected for providing a message for transmission and is termed the "ONLINE STORE", the other store is available for preparation of the new (or subsequent) message, without disturbing the online transmission and is referred to as the "STANDBY STORE".

Making the selection of which store is online and preparation of messages are examples of the functions that are generally carried out from the remote control.

The main equipment is contained in a "SUB-RACK" suited for installation in an equipment room, which supports a remote control panel, controls are a group of illuminated press buttons.

A duplicate of the controls are fitted on the subrack and they may be used by personnel who have a key for the lock on the switch panel.

When the key is turned to the "LOCAL" position no remote commands are accepted.

Remote control commands are carried to the main equipment by the use of a twenty five way multicore cable, a second cable is used to connect the audio signals from the R.C.U.

The audio output, from the sub-rack, is sampled to ensure that it remains within specification. Should the output level fall or be inaudible the ALARM will break a normally closed dry contact.

Another dry contact is provided to key the external radio transmitter.