Under the leadership of Jay Stoffer , Delphi developed a proprietary system called Delta 1 that picked up incoming calls directly from the telephone company .
Another company , Delphi Communications of California , deserves some partial credit for invention of voicemail .
Under the leadership of Jay Stoffer , Delphi Communications developed a proprietary system called Delta 1 that picked up incoming calls directly from the telephone company .
Another company , Delphi Communications of California , deserves some partial credit for invention of voicemail .