code: public byte[] bindResp(int commandId, int sequenceNumber, String systemId,
              OptionalParameter... optionalParameters) throws PDUStringException {
          StringValidator.validateString(systemId, StringParameter.SYSTEM_ID);
          PDUByteBuffer buf = new PDUByteBuffer(commandId, 0, sequenceNumber);
          buf.append(systemId);
          buf.appendAll(optionalParameters);
          return buf.toBytes();
      }
docs: /*
  (non-Javadoc)
  
  @see org.jsmpp.util.PDUComposer#bindResp(int, int, java.lang.String,
  org.jsmpp.bean.OptionalParameter[])