diff --git a/converter/ibmpc_usb/config.h b/converter/ibmpc_usb/config.h
index 2489d4da..bf61aa6d 100644
--- a/converter/ibmpc_usb/config.h
+++ b/converter/ibmpc_usb/config.h
@@ -38,6 +38,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
     keyboard_report->mods == (MOD_BIT(KC_LALT) | MOD_BIT(KC_RALT)) \
 )
 
+
+// CS2 80-prefixed codes support
+#define CS2_80CODE_SUPPORT
+
 // G80-2551 terminal keyboard support
 #define G80_2551_SUPPORT
 
diff --git a/converter/ibmpc_usb/ibmpc_usb.cpp b/converter/ibmpc_usb/ibmpc_usb.cpp
index 89c3a71f..dba6c3d4 100644
--- a/converter/ibmpc_usb/ibmpc_usb.cpp
+++ b/converter/ibmpc_usb/ibmpc_usb.cpp
@@ -928,6 +928,37 @@ uint8_t IBMPCConverter::cs2_e0code(uint8_t code) {
     }
 }
 
+#ifdef CS2_80CODE_SUPPORT
+// 80-prefixed codes
+uint8_t IBMPCConverter::cs2_80code(uint8_t code) {
+    // Tandberg TDV 5020
+    // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#tandberg-tdv-5020
+    switch (code) {
+        case 0x2B: return 0x08; // TDV:MERK  (mark)                 -> F13
+        case 0x34: return 0x10; // TDV:ANGRE (undo)                 -> F14
+        case 0x33: return 0x18; // TDV:SKRIV (print)                -> F15
+        case 0x42: return 0x20; // TDV:SLUTT (end)                  -> F16
+        case 0x2C: return 0x28; // TDV:STRYK (cut)                  -> F17
+        case 0x3C: return 0x30; // TDV:KOPI  (copy)                 -> F18
+        case 0x43: return 0x38; // TDV:FLYTT (move)                 -> F19
+        case 0x4B: return 0x40; // TDV:FELT  (cell)                 -> F20
+        case 0x2A: return 0x48; // TDV:AVSN  (paragraph)            -> F21
+        case 0x32: return 0x50; // TDV:SETN  (sentence)             -> F22
+        case 0x3A: return 0x57; // TDV:ORD   (word)                 -> F23
+        case 0x61: return 0x6A; // TDV:⮎     (?)                    -> JYEN Japanese Yen
+        case 0x1D: return 0x5F; // TDV:HJELP (help)                 -> F24
+        case 0x24: return 0x17; // TDV:^^^   (?)                    -> LGUI
+        case 0x44: return 0x65; // TDV:>>/<< (left/right adjust)    -> VOLD Volume Down
+        case 0x4D: return 0x6E; // TDV:JUST  (adjust)               -> VOLU Volume Up
+        case 0x1C: return 0x6F; // TDV:>< <> (center/block)         -> MUTE
+        case 0x2D: return 0x51; // TDV:⇟     (three lines down)     -> RO   Japanese Ro
+        case 0x1B: return 0x1F; // TDV:⇤     (start of line)        -> RGUI
+        case 0x23: return 0x27; // TDV:⇥     (end of line)          -> APP
+    }
+    return code;
+}
+#endif
+
 // IBM 5576-002/003 Scan code translation
 // https://github.com/tmk/tmk_keyboard/wiki/IBM-PC-AT-Keyboard-Protocol#ibm-5576-code-set-82h
 uint8_t IBMPCConverter::translate_5576_cs2(uint8_t code) {
@@ -969,6 +1000,11 @@ int8_t IBMPCConverter::process_cs2(uint8_t code)
                 case 0xE1:
                     state_cs2 = CS2_E1;
                     break;
+#ifdef CS2_80CODE_SUPPORT
+                case 0x80:
+                    state_cs2 = CS2_80;
+                    break;
+#endif
                 case 0x83:  // F7
                     matrix_make(0x02);
                     state_cs2 = CS2_INIT;
@@ -1110,6 +1146,25 @@ int8_t IBMPCConverter::process_cs2(uint8_t code)
                     state_cs2 = CS2_INIT;
             }
             break;
+#ifdef CS2_80CODE_SUPPORT
+        case CS2_80:
+            switch (code) {
+                case 0xF0:
+                    state_cs2 = CS2_80_F0;
+                    break;
+                default:
+                    state_cs2 = CS2_INIT;
+                    matrix_make(cs2_80code(code));
+            }
+            break;
+        case CS2_80_F0:
+            switch (code) {
+                default:
+                    state_cs2 = CS2_INIT;
+                    matrix_break(cs2_80code(code));
+            }
+            break;
+#endif
         default:
             state_cs2 = CS2_INIT;
     }
diff --git a/converter/ibmpc_usb/ibmpc_usb.hpp b/converter/ibmpc_usb/ibmpc_usb.hpp
index 9d924069..acb6d1fa 100644
--- a/converter/ibmpc_usb/ibmpc_usb.hpp
+++ b/converter/ibmpc_usb/ibmpc_usb.hpp
@@ -95,6 +95,10 @@ class IBMPCConverter {
         CS2_E1_F0,
         CS2_E1_F0_14,
         CS2_E1_F0_14_F0,
+#ifdef CS2_80CODE_SUPPORT
+        CS2_80,
+        CS2_80_F0,
+#endif
     } state_cs2 = CS2_INIT;
 
     enum CS3_state {
@@ -112,6 +116,9 @@ class IBMPCConverter {
     int8_t process_cs3(uint8_t code);
     uint8_t cs1_e0code(uint8_t code);
     uint8_t cs2_e0code(uint8_t code);
+#ifdef CS2_80CODE_SUPPORT
+    uint8_t cs2_80code(uint8_t code);
+#endif
     uint8_t translate_5576_cs2(uint8_t code);
     uint8_t translate_5576_cs2_e0(uint8_t code);
     uint8_t translate_5576_cs3(uint8_t code);