BindTransmitterResp(ByteBuffer bb) throws PduException {
   super(bb);
   try {
     systemId = bb.removeCString();
   } catch (TerminatingNullNotFoundException e) {
     throw new PduException("System id parsing failed.", e);
   }
 }
 @Override
 protected ByteBuffer body() {
   ByteBuffer bb = new ByteBuffer();
   bb.appendCString(systemId);
   return bb;
 }