diff --git a/known_services b/known_services
index e20a80a..f3cca58 100644
--- a/known_services
+++ b/known_services
@@ -10,4 +10,5 @@ SERVICEDATA=(\
   "Ceefax (Worldwide),svn,https://internal.nathanmediaservices.co.uk/svn/ceefax/Worldwide,Ceefax/regional,Ceefax" \
   "Ceefax (Yorks and Lincs),svn,https://internal.nathanmediaservices.co.uk/svn/ceefax/Yorks&Lincs,Ceefax/regional,Ceefax" \
   "Chunkytext,git,https://zxnet.co.uk/git/cf.git,Chunkytext," \
+  "SPARK,git,https://github.com/ZXGuesser/spark-teletext.git,SPARK," \
 )
diff --git a/ttxline.cpp b/ttxline.cpp
index cd52bc2..3cadb1e 100644
--- a/ttxline.cpp
+++ b/ttxline.cpp
@@ -66,19 +66,23 @@ std::string TTXLine::validate(std::string const& val)
     std::string str="                                        ";
     for (unsigned int i=0;i<val.length() && j<40;i++)
     {
-        ch=val[i] & 0x7f;   // Convert to 7 bits
-        
-        if (ch==0x1b) // escape?
+        ch = val[i] & 0x7f; // 7-bit
+
+        if (val[i] == 0x1b) // ascii escape
         {
             i++;
-            ch=(val[i] & 0x3f);
+            ch = val[i] & 0x3f;
         }
-        
-        if (ch==0)
+        else if ((uint8_t)val[i] < 0x20) // other ascii control code
         {
-            ch=0x80; // set high bit to escape nulls in strings
+            break;
         }
-        
+
+        if (ch < 0x20)
+        {
+            ch |= 0x80; // set high bit on control codes
+        }
+
         str[j++]=ch;
     }
     return str;
diff --git a/ttxpage.cpp b/ttxpage.cpp
index 9b419fd..f74e89e 100644
--- a/ttxpage.cpp
+++ b/ttxpage.cpp
@@ -248,19 +248,15 @@ bool TTXPage::m_LoadTTI(std::string filename)
                     std::getline(filein, line); // Mask is intended for TED to protecting regions from editing.
                     break;
                 case 8 : // "OL" - Output line
-                    // OL,9,ƒA-Z INDEX     ‡199ƒNEWS HEADLINES  ‡101
                     std::getline(filein, line, ',');
                     lineNumber=atoi(line.c_str());
                     std::getline(filein, line);
                     if (lineNumber>MAXROW) break;
-                    // std::cerr << "reading " << lineNumber << " line=" << line << std::endl;
                     p->SetRow(lineNumber,line);
-                    // std::cerr << lineNumber << ": OL partly implemented. " << line << std::endl;
                     lines++;
                     break;
                 case 9 : // "FL"; - Fastext links
                     // FL,104,104,105,106,F,100
-                    // std::cerr << "FL not implemented\n";
                     for (int fli=0;fli<6;fli++)
                     {
                         if (fli<5)