Thanks, Lochias.
The web page at
Solid State Cockpit Voice Recorder (SSCVR) - Honeywell Aerospace(at least for Honeyell SSCVRs) confirms what you say: "Must be removed from aircraft for download."
The document at
http://www.honeywell.com/sites/servl...6-9046902324E8 (page 12) has a diagram that shows a PC with an audio board and a cable connected to the SSCVR in a Playback and Test Station (PATS).
So, as you say, it's a bench job rather than an "open an access panel on the a/c and plug a laptop in."
Regards
Andy.