diff --git a/document.cpp b/document.cpp
index d0c2d48..eed8c20 100644
--- a/document.cpp
+++ b/document.cpp
@@ -99,8 +99,8 @@ void TeletextDocument::loadDocument(QFile *inFile)
 			bool pageStatusOk;
 			int pageStatusRead = inLine.mid(3, 4).toInt(&pageStatusOk, 16);
 			if (pageStatusOk) {
-				loadingPage->setControlBit(0, pageStatusRead & 0x4000);
-				for (int i=1, pageStatusBit=0x0001; i<8; i++, pageStatusBit<<=1)
+				loadingPage->setControlBit(PageBase::C4ErasePage, pageStatusRead & 0x4000);
+				for (int i=PageBase::C5Newsflash, pageStatusBit=0x0001; i<=PageBase::C11SerialMagazine; i++, pageStatusBit<<=1)
 					loadingPage->setControlBit(i, pageStatusRead & pageStatusBit);
 				loadingPage->setDefaultNOS(((pageStatusRead & 0x0200) >> 9) | ((pageStatusRead & 0x0100) >> 7) | ((pageStatusRead & 0x0080) >> 5));
 			}
diff --git a/levelonepage.cpp b/levelonepage.cpp
index 57c0d44..f15782a 100644
--- a/levelonepage.cpp
+++ b/levelonepage.cpp
@@ -42,7 +42,7 @@ LevelOnePage::LevelOnePage(const PageBase &other)
 	localEnhance.reserve(208);
 	clearPage();
 
-	for (int i=0; i<8; i++)
+	for (int i=PageBase::C4ErasePage; i<=PageBase::C11SerialMagazine; i++)
 		setControlBit(i, other.controlBit(i));
 	for (int i=0; i<90; i++)
 		if (other.packetNeededArrayIndex(i))
@@ -426,8 +426,8 @@ void LevelOnePage::savePage(QTextStream *outStream, int pageNumber, int subPageN
 int LevelOnePage::controlBitsToPS() const
 {
 	//TODO map page language for regions other than 0
-	int pageStatus = 0x8000 | (controlBit(0) << 14) | ((m_defaultNOS & 1) << 9) | ((m_defaultNOS & 2) << 7) | ((m_defaultNOS & 4) << 5);
-	for (int i=1; i<8; i++)
+	int pageStatus = 0x8000 | (controlBit(PageBase::C4ErasePage) << 14) | ((m_defaultNOS & 1) << 9) | ((m_defaultNOS & 2) << 7) | ((m_defaultNOS & 4) << 5);
+	for (int i=C5Newsflash; i<=C11SerialMagazine; i++)
 		pageStatus |= controlBit(i) << (i-1);
 	return pageStatus;
 }
diff --git a/pagebase.cpp b/pagebase.cpp
index 2063653..1536dfc 100644
--- a/pagebase.cpp
+++ b/pagebase.cpp
@@ -26,13 +26,13 @@ PageBase::PageBase()
 	// We use nullptrs to keep track of allocated packets, so initialise them this way
 	for (int i=0; i<90; i++)
 		m_packets[i] = nullptr;
-	for (int i=0; i<8; i++)
+	for (int i=PageBase::C4ErasePage; i<=PageBase::C11SerialMagazine; i++)
 		m_controlBits[i] = false;
 }
 
 PageBase::PageBase(const PageBase &other)
 {
-	for (int i=0; i<8; i++)
+	for (int i=PageBase::C4ErasePage; i<=PageBase::C11SerialMagazine; i++)
 		setControlBit(i, other.controlBit(i));
 	for (int i=0; i<90; i++)
 		if (other.packetNeededArrayIndex(i))
diff --git a/pagebase.h b/pagebase.h
index 53530f6..25ebcd1 100644
--- a/pagebase.h
+++ b/pagebase.h
@@ -28,6 +28,8 @@ class PageBase //: public QObject
 	//Q_OBJECT
 
 public:
+	enum ControlBitsEnum { C4ErasePage, C5Newsflash, C6Subtitle, C7SuppressHeader, C8Update, C9InterruptedSequence, C10InhibitDisplay, C11SerialMagazine };
+
 	PageBase();
 	PageBase(const PageBase &);
 	~PageBase();
diff --git a/render.cpp b/render.cpp
index 654b531..095ce5c 100644
--- a/render.cpp
+++ b/render.cpp
@@ -321,14 +321,14 @@ void TeletextPageRender::renderPage(int r)
 			return;
 		int charWidth = resultAttributes.display.doubleWidth ? 24 : 12;
 		int charHeight = resultAttributes.display.doubleHeight ? 20 : 10;
-		bool transparentBackground = (m_levelOnePage->controlBit(1) || m_levelOnePage->controlBit(2) || m_mix) && !resultAttributes.display.boxingWindow;
+		bool transparentBackground = (m_levelOnePage->controlBit(PageBase::C5Newsflash) || m_levelOnePage->controlBit(PageBase::C6Subtitle) || m_mix) && !resultAttributes.display.boxingWindow;
 		// bool transparentForeground = false;
 		if (transparentBackground) {
 			pixmapPainter.setCompositionMode(QPainter::CompositionMode_Clear);
 			pixmapPainter.eraseRect(c*12, r*10, charWidth, charHeight);
 			pixmapPainter.setCompositionMode(QPainter::CompositionMode_SourceOver);
 		}
-		if ((m_levelOnePage->controlBit(1) || m_levelOnePage->controlBit(2)) && !resultAttributes.display.boxingWindow) {
+		if ((m_levelOnePage->controlBit(PageBase::C5Newsflash) || m_levelOnePage->controlBit(PageBase::C6Subtitle)) && !resultAttributes.display.boxingWindow) {
 			// Outside a boxed area
 			resultCharacter = { 0x20, 0, 0 };
 			underlined = false;
@@ -629,7 +629,7 @@ void TeletextPageRender::updateFlashRequired(int newFlashRequired)
 
 inline void TeletextPageRender::setFullScreenColour(int newColour)
 {
-	if (m_mix || m_levelOnePage->controlBit(1) || m_levelOnePage->controlBit(2)) {
+	if (m_mix || m_levelOnePage->controlBit(PageBase::C5Newsflash) || m_levelOnePage->controlBit(PageBase::C6Subtitle)) {
 		m_finalFullScreenQColor = QColor(0, 0, 0, 0);
 		emit fullScreenColourChanged(QColor(0, 0, 0, 0));
 		return;
@@ -644,7 +644,7 @@ inline void TeletextPageRender::setFullScreenColour(int newColour)
 
 inline void TeletextPageRender::setFullRowColour(int row, int newColour)
 {
-	if (m_mix || m_levelOnePage->controlBit(1) || m_levelOnePage->controlBit(2)) {
+	if (m_mix || m_levelOnePage->controlBit(PageBase::C5Newsflash) || m_levelOnePage->controlBit(PageBase::C6Subtitle)) {
 		m_fullRowQColor[row] = QColor(0, 0, 0, 0);
 		emit fullRowColourChanged(row, QColor(0, 0, 0, 0));
 		return;