diff --git a/src/common/parser/Constants.ts b/src/common/parser/Constants.ts
index 1468c3bbb..fec3cee33 100644
--- a/src/common/parser/Constants.ts
+++ b/src/common/parser/Constants.ts
@@ -14,7 +14,7 @@ export const enum ParserState {
   CSI_PARAM = 4,
   CSI_INTERMEDIATE = 5,
   CSI_IGNORE = 6,
-  SOS_PM_APC_STRING = 7,
+  SOS_PM_STRING = 7,
   OSC_STRING = 8,
   DCS_ENTRY = 9,
   DCS_PARAM = 10,
diff --git a/src/common/parser/EscapeSequenceParser.test.ts b/src/common/parser/EscapeSequenceParser.test.ts
index 5c754a203..799b43d2b 100644
--- a/src/common/parser/EscapeSequenceParser.test.ts
+++ b/src/common/parser/EscapeSequenceParser.test.ts
@@ -156,7 +156,7 @@ const states: number[] = [
   ParserState.CSI_PARAM,
   ParserState.CSI_INTERMEDIATE,
   ParserState.CSI_IGNORE,
-  ParserState.SOS_PM_APC_STRING,
+  ParserState.SOS_PM_STRING,
   ParserState.OSC_STRING,
   ParserState.DCS_ENTRY,
   ParserState.DCS_PARAM,
@@ -703,13 +703,13 @@ describe('EscapeSequenceParser', () => {
         testTerminal.clear();
       }
     });
-    it('trans ANYWHERE/ESCAPE --> SOS_PM_APC_STRING', () => {
+    it('trans ANYWHERE/ESCAPE --> SOS_PM_STRING', () => {
       parser.reset();
       // C0 (only SOS and PM, APC has separate handling)
       let initializers = ['\x58', '\x5e'];
       for (let i = 0; i < initializers.length; ++i) {
         parse(parser, '\x1b' + initializers[i]);
-        assert.equal(parser.currentState, ParserState.SOS_PM_APC_STRING);
+        assert.equal(parser.currentState, ParserState.SOS_PM_STRING);
         parser.reset();
       }
       // C1 (only SOS and PM, APC has separate handling)
@@ -718,7 +718,7 @@ describe('EscapeSequenceParser', () => {
         initializers = ['\x98', '\x9e'];
         for (let i = 0; i < initializers.length; ++i) {
           parse(parser, initializers[i]);
-          assert.equal(parser.currentState, ParserState.SOS_PM_APC_STRING);
+          assert.equal(parser.currentState, ParserState.SOS_PM_STRING);
           parser.reset();
         }
       }
@@ -737,16 +737,16 @@ describe('EscapeSequenceParser', () => {
         parser.reset();
       }
     });
-    it('state SOS_PM_APC_STRING ignore rules', () => {
+    it('state SOS_PM_STRING ignore rules', () => {
       parser.reset();
       let ignored = r(0x00, 0x18);
       ignored = ignored.concat(['\x19']);
       ignored = ignored.concat(r(0x1c, 0x20));
       ignored = ignored.concat(r(0x20, 0x80));
       for (let i = 0; i < ignored.length; ++i) {
-        parser.currentState = ParserState.SOS_PM_APC_STRING;
+        parser.currentState = ParserState.SOS_PM_STRING;
         parse(parser, ignored[i]);
-        assert.equal(parser.currentState, ParserState.SOS_PM_APC_STRING);
+        assert.equal(parser.currentState, ParserState.SOS_PM_STRING);
         parser.reset();
       }
     });
diff --git a/src/common/parser/EscapeSequenceParser.ts b/src/common/parser/EscapeSequenceParser.ts
index 710ac10f0..60396c1e0 100644
--- a/src/common/parser/EscapeSequenceParser.ts
+++ b/src/common/parser/EscapeSequenceParser.ts
@@ -105,7 +105,7 @@ export const VT500_TRANSITION_TABLE = (function(): TransitionTable {
     table.add(0x9c, state, ParserAction.IGNORE, ParserState.GROUND); // ST as terminator
     table.add(0x1b, state, ParserAction.CLEAR, ParserState.ESCAPE);  // ESC
     table.add(0x9d, state, ParserAction.OSC_START, ParserState.OSC_STRING);  // OSC
-    table.addMany([0x98, 0x9e], state, ParserAction.IGNORE, ParserState.SOS_PM_APC_STRING);  // SOS, PM
+    table.addMany([0x98, 0x9e], state, ParserAction.IGNORE, ParserState.SOS_PM_STRING);  // SOS, PM
     table.add(0x9f, state, ParserAction.APC_START, ParserState.APC_STRING);  // APC
     table.add(0x9b, state, ParserAction.CLEAR, ParserState.CSI_ENTRY);  // CSI
     table.add(0x90, state, ParserAction.CLEAR, ParserState.DCS_ENTRY);  // DCS
@@ -130,13 +130,18 @@ export const VT500_TRANSITION_TABLE = (function(): TransitionTable {
   table.add(0x7f, ParserState.OSC_STRING, ParserAction.OSC_PUT, ParserState.OSC_STRING);
   table.addMany([0x9c, 0x1b, 0x18, 0x1a, 0x07], ParserState.OSC_STRING, ParserAction.OSC_END, ParserState.GROUND);
   table.addMany(r(0x1c, 0x20), ParserState.OSC_STRING, ParserAction.IGNORE, ParserState.OSC_STRING);
-  // sos/pm/apc - sos/pm does nothing, apc gets separate handling
-  table.addMany([0x58, 0x5e], ParserState.ESCAPE, ParserAction.IGNORE, ParserState.SOS_PM_APC_STRING);  // SOS, PM
-  table.add(0x5f, ParserState.ESCAPE, ParserAction.APC_START, ParserState.APC_STRING);  // APC ('_')
-  table.addMany(PRINTABLES, ParserState.SOS_PM_APC_STRING, ParserAction.IGNORE, ParserState.SOS_PM_APC_STRING);
-  table.addMany(EXECUTABLES, ParserState.SOS_PM_APC_STRING, ParserAction.IGNORE, ParserState.SOS_PM_APC_STRING);
-  table.add(0x9c, ParserState.SOS_PM_APC_STRING, ParserAction.IGNORE, ParserState.GROUND);
-  table.add(0x7f, ParserState.SOS_PM_APC_STRING, ParserAction.IGNORE, ParserState.SOS_PM_APC_STRING);
+  // sos/pm
+  table.addMany([0x58, 0x5e], ParserState.ESCAPE, ParserAction.IGNORE, ParserState.SOS_PM_STRING);
+  table.addMany(PRINTABLES, ParserState.SOS_PM_STRING, ParserAction.IGNORE, ParserState.SOS_PM_STRING);
+  table.addMany(EXECUTABLES, ParserState.SOS_PM_STRING, ParserAction.IGNORE, ParserState.SOS_PM_STRING);
+  table.add(0x9c, ParserState.SOS_PM_STRING, ParserAction.IGNORE, ParserState.GROUND);
+  table.add(0x7f, ParserState.SOS_PM_STRING, ParserAction.IGNORE, ParserState.SOS_PM_STRING);
+  // apc
+  table.add(0x5f, ParserState.ESCAPE, ParserAction.APC_START, ParserState.APC_STRING);
+  table.addMany(PRINTABLES, ParserState.APC_STRING, ParserAction.APC_PUT, ParserState.APC_STRING);
+  table.addMany(EXECUTABLES, ParserState.APC_STRING, ParserAction.IGNORE, ParserState.APC_STRING);
+  table.add(0x7f, ParserState.APC_STRING, ParserAction.IGNORE, ParserState.APC_STRING);
+  table.addMany([0x1b, 0x9c, 0x18, 0x1a], ParserState.APC_STRING, ParserAction.APC_END, ParserState.GROUND);
   // csi entries
   table.add(0x5b, ParserState.ESCAPE, ParserAction.CLEAR, ParserState.CSI_ENTRY);
   table.addMany(r(0x40, 0x7f), ParserState.CSI_ENTRY, ParserAction.CSI_DISPATCH, ParserState.GROUND);
@@ -190,11 +195,6 @@ export const VT500_TRANSITION_TABLE = (function(): TransitionTable {
   table.addMany(PRINTABLES, ParserState.DCS_PASSTHROUGH, ParserAction.DCS_PUT, ParserState.DCS_PASSTHROUGH);
   table.add(0x7f, ParserState.DCS_PASSTHROUGH, ParserAction.IGNORE, ParserState.DCS_PASSTHROUGH);
   table.addMany([0x1b, 0x9c, 0x18, 0x1a], ParserState.DCS_PASSTHROUGH, ParserAction.DCS_UNHOOK, ParserState.GROUND);
-  // apc passthrough - similar to DCS passthrough
-  table.addMany(PRINTABLES, ParserState.APC_STRING, ParserAction.APC_PUT, ParserState.APC_STRING);
-  table.addMany(EXECUTABLES, ParserState.APC_STRING, ParserAction.IGNORE, ParserState.APC_STRING);
-  table.add(0x7f, ParserState.APC_STRING, ParserAction.IGNORE, ParserState.APC_STRING);
-  table.addMany([0x1b, 0x9c, 0x18, 0x1a], ParserState.APC_STRING, ParserAction.APC_END, ParserState.GROUND);
   // special handling of unicode chars
   table.add(NON_ASCII_PRINTABLE, ParserState.GROUND, ParserAction.PRINT, ParserState.GROUND);
   table.add(NON_ASCII_PRINTABLE, ParserState.OSC_STRING, ParserAction.OSC_PUT, ParserState.OSC_STRING);