The VoiceToDataAnswer entries give a sequence of commands Unimodem/V can send to your modem to switch it to data answering mode after it has been in voice answering mode. For example, SMPVOICE.INF uses the following sequence of commands for switching voice to data mode switching:
HKR, VoiceToDataAnswer, 1,, "at#cls=0cr" (select data)
HKR, VoiceToDataAnswer, 2,, "atacr" (answer)
Note that Unimodem/V answers all incoming calls on voice modems as voice calls.