User Guide
Series III Avionics
Pilot's Guide
Page 40
TTS - (Time-To-Station) While this switch is held
pressed, time-to-station will be shown on the
display above the switch. When the switch is
released, the display returns to its previous readout
of ground speed. If in hold when the TTS switch is
pressed, the HLD FREQ on the display will blink
twice to alert the pilot.
NOTE:
When DME is being tuned by an MLS,
receive DME hold is inhibited.