def send_sms number, message, opts={}
      wait       =!(opts[:nowait] || false)
      encode    =  opts[:encode] || :ascii
      sender    =  opts[:sender] || false
      datetime  =  opts[:date]   || false

      case encode
        when :binary || :base64
          encode = 'B'
        when :unicode
          encode = 'U'
        else # :ascii
          encode = ''
      end

      if sender
        sender = "#{sender} "
        custom = 'F'
      else
        custom = ''
      end

      if datetime
        datetime = "#{datetime} "
        date = 'D'
      else
        date = ''
      end

      cmd_raw "#{date}#{custom}#{encode}SUBMIT", "#{datetime}#{sender}#{number} #{message}"

      if wait
        wait_for last_label
        return false if @response_cmd.eql? 'NOOK'
        return "#{@response_args[0]}.#{@response_args[1]}".to_f
      end
    end
def send_sms number, message, opts={}
      wait       =!(opts[:nowait] || false)
      encode    =  opts[:encode] || :ascii
      sender    =  opts[:sender] || false
      datetime  =  opts[:date]   || false

      case encode
        when :binary || :base64
          encode = 'B'
        when :unicode
          encode = 'U'
        else # :ascii
          encode = ''
      end

      if sender
        sender = "#{sender} "
        custom = 'F'
      else
        custom = ''
      end

      if datetime
        datetime = "#{datetime} "
        date = 'D'
      else
        date = ''
      end

      cmd_raw "#{date}#{custom}#{encode}SUBMIT", "#{datetime}#{sender}#{number} #{message}"

      if wait
        wait_for last_label
        return false if @response_cmd.eql? 'NOOK'
        return "#{@response_args[0]}.#{@response_args[1]}".to_f
      end
    end
number
   The telephone number
 message
   The string to send
 opts
   - nowait: (default false) no wait for response
   - sender: The sender telephone number
   - date: Date and time to send message in format YYYYMMDDhhmm[+-]ZZzz
   - encode
       * :ascii (default)
       * :binary message is in base64 encoded
       * :base64 message is in base64 encoded
       * :unicode message is in unicode and base64 encoded