The unit takes the latest recording as its stop time and fits as much of the previous recording
as the CD will hold.

А весь абзац выглядит следующим образом:
Pressing the Record CD button while viewing live video will cause the Archive Incident screen to
appear. The unit takes the latest recording as its stop time and fits as much of the previous recording
as the CD will hold. The time and size of the archived video can be adjusted by various amounts
depending on where on the Hard Disk the data lies.

Заранее спасибо

Устройство воспринимает время последней запись в качестве ограничителя и архивирует предпоследнюю запись в размере, не превышающем емкости CD.