Voice recorders were retrofitted into planes already in service.

录音设备安在了正在服役的飞机上。

《牛津词典》

Many writers use voice recorders.

许多作家都会用录音笔。

youdao

DSS is used by almost all Olympus Digital Voice Recorders.

支援几乎所有的奥林巴斯数码录音机。

youdao

But the only record of all cockpit conversations - the planes' voice recorders - may not have survived, said Mr Learmount.

BBC: Cockpit drama of doomed planes

But last time I checked, big companies like Sony, Panasonic, Olympus, RCA and others were still profitably making digital voice recorders.

FORBES: Video Killed the Radio Star, But Smartphones Did NOT Kill the Flip Cam

The investigation will include scrutiny of the flight and voice data recorders, it said.

CNN: Report: Stray jet's pilots were on laptops