Lathem Airtime AT-DDC4 - Manual (Page 4)

Page 2
Time Formats
The AT-DDC4 Series Wall Clocks can be set to display in 12 Hour or 24
Hour format. When in 12 Hour format, a red LED in the upper left
corner of the display indicates PM hours. When in 24 Hour format, the
hours are displays in Military style.
Front Panel
To set the display format, use the jumper (J1) located on the back of
the circuit board which can be accessed by removing the right side end
cap and sliding the circuit board out slightly.
Back Side of Circuit Board
Jumper J1
On = 12 Hour display
Off = 24 Hour display