If your voice modem offers distinctive ring support and you want Unimodem/V to use it, then you must add a EnableDistinctiveRing key to the registry. The value of the key is the command string Unimodem/V can send to your modem to enable distinctive ring support. For example, the SMPVOICE.INF file contains the following item:
HKR, EnableDistinctiveRing, 1,, "at-sdr=7cr"
Since the Distinctive Ring information returned by your modem is a variable-length string, you must specify the string terminator characters. For example, the SMPVOICE.INF file contains the following item:
HKR,, VariableTerminator,,