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

I bought a lot of limited-use tech gadgets, like voice recorders and expensive digital cameras.

我买了许多用途有限的科技产品，比如录音机和昂贵的数码相机。

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