Thermionic Series Three. Multichonnel Recorders. Built up from different a rrangements of the units shown, a range of installations is available to meet the requirements of Air Traffic Control Centres of all types. Installations may consist of one, two, or three racks of equipment with ployback built in or separate. Automatic monitoring and various other features are optional.

Playback Unit
Provides for the Replay of up to three channels simultaneously,TIME INJECTION UNIT
A crystal controlled clock schedules Coded Time Signals (or recording in parallel with communications.)

TAPE DECK
Handles 12 hour reels of or various sizes of tapes for recordIngup to 10. 15 or 20 tracks. .
Automatic switching to other units is built in to provide ,. long periods ofcontinuous recording. Full, fast spooling facilities are provided with a time co librated tachometer.

RECORDING UNIT
Provides a plug-in printed circuit transistor amplifier for each channel to be recorded, together with bias oscillator and pilot signal oscillator.

POWER SUPPLY UNIT
Provides all the internal power requirements for a single rack of equipment from the mains supply, with a built-in transistor stabilising unit.

AUTOMATIC MONITOR
For each channel a control amplifier is provided to utilise the pilot signal to control the emergency changeover to automatic spare channel or to a second recorder unit, providing a guarantee of continuous recording .

BLOWER UNIT
Provides cabinet pressurisation with a supply of filtered air for cooling or heating as required.