/// <summary>
/// Send dtmf digit
/// </summary>
/// <param name="sessionId"></param>
/// <param name="digits"></param>
/// <param name="mode"></param>
/// <returns></returns>
public override bool dialDtmf(string digits, EDtmfMode mode)
{
int status = PjsipMethods.dll_dialDtmf(SessionId, digits, (int)mode);
return(true);
}