The recording workstation used for POLYPHONE was based on an Aculab telephone interface, a Rhetorex Voice Card and driver software, Show-'n-Tel application development software, and a 16 port operational license, in an OS/2 PC. Each item recorded was stored in a separate file; all files were copied to a UNIX network for transliteration and archiving.
The recording platform was set up to record and store the speech signals in
A-law format. Because the Dutch
PSTN is completely digital, the acoustic quality of the recordings
is determined by the characteristics of the caller's local loop and
the background noise in the caller's location.