diff --git a/src/Window.zig b/src/Window.zig
index 7b533a0ee..575680dc4 100644
--- a/src/Window.zig
+++ b/src/Window.zig
@@ -1552,7 +1552,8 @@ pub fn deviceAttributes(
     _ = params;
 
     switch (req) {
-        .primary => self.queueWrite("\x1B[?6c") catch |err|
+        // VT220
+        .primary => self.queueWrite("\x1B[?62;c") catch |err|
             log.warn("error queueing device attr response: {}", .{err}),
         else => log.warn("unimplemented device attributes req: {}", .{req}),
     }
@@ -1640,3 +1641,12 @@ pub fn configureCharset(
 ) !void {
     self.terminal.configureCharset(slot, set);
 }
+
+pub fn invokeCharset(
+    self: *Window,
+    active: terminal.CharsetActiveSlot,
+    slot: terminal.CharsetSlot,
+    single: bool,
+) !void {
+    self.terminal.invokeCharset(active, slot, single);
+}
diff --git a/src/terminal/Terminal.zig b/src/terminal/Terminal.zig
index ba40fb19a..f733f1f17 100644
--- a/src/terminal/Terminal.zig
+++ b/src/terminal/Terminal.zig
@@ -399,6 +399,22 @@ pub fn configureCharset(self: *Terminal, slot: charsets.Slots, set: charsets.Cha
     self.charset.charsets.set(slot, set);
 }
 
+/// Invoke the charset in slot into the active slot. If single is true,
+/// then this will only be invoked for a single character.
+pub fn invokeCharset(
+    self: *Terminal,
+    active: charsets.ActiveSlot,
+    slot: charsets.Slots,
+    single: bool,
+) void {
+    assert(!single); // TODO
+
+    switch (active) {
+        .GL => self.charset.gl = slot,
+        .GR => self.charset.gr = slot,
+    }
+}
+
 pub fn print(self: *Terminal, c: u21) !void {
     const tracy = trace(@src());
     defer tracy.end();
@@ -1306,6 +1322,26 @@ test "Terminal: print charset" {
     }
 }
 
+test "Terminal: print invoke charset" {
+    var t = try init(testing.allocator, 80, 80);
+    defer t.deinit(testing.allocator);
+
+    t.configureCharset(.G1, .dec_special);
+
+    // Basic grid writing
+    try t.print('`');
+    t.invokeCharset(.GL, .G1, false);
+    try t.print('`');
+    try t.print('`');
+    t.invokeCharset(.GL, .G0, false);
+    try t.print('`');
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("`◆◆`", str);
+    }
+}
+
 test "Terminal: linefeed and carriage return" {
     var t = try init(testing.allocator, 80, 80);
     defer t.deinit(testing.allocator);
diff --git a/src/terminal/charsets.zig b/src/terminal/charsets.zig
index 798adb326..e6ebe21aa 100644
--- a/src/terminal/charsets.zig
+++ b/src/terminal/charsets.zig
@@ -9,6 +9,9 @@ pub const Slots = enum(u3) {
     G3 = 3,
 };
 
+/// The name of the active slots.
+pub const ActiveSlot = enum { GL, GR };
+
 /// The list of supported character sets and their associated tables.
 pub const Charset = enum {
     utf8,
diff --git a/src/terminal/main.zig b/src/terminal/main.zig
index ae10f8e7c..a1a1d0d34 100644
--- a/src/terminal/main.zig
+++ b/src/terminal/main.zig
@@ -10,6 +10,7 @@ pub const color = @import("color.zig");
 
 pub const Charset = charsets.Charset;
 pub const CharsetSlot = charsets.Slots;
+pub const CharsetActiveSlot = charsets.ActiveSlot;
 pub const Terminal = @import("Terminal.zig");
 pub const Parser = @import("Parser.zig");
 pub const Selection = @import("Selection.zig");
diff --git a/src/terminal/stream.zig b/src/terminal/stream.zig
index 4219f9551..f6778b575 100644
--- a/src/terminal/stream.zig
+++ b/src/terminal/stream.zig
@@ -109,8 +109,15 @@ pub fn Stream(comptime Handler: type) type {
                 else
                     log.warn("unimplemented execute: {x}", .{c}),
 
-                // TODO
-                .SO, .SI => log.warn("TODO: Shift out/Shift in", .{}),
+                .SO => if (@hasDecl(T, "invokeCharset"))
+                    try self.handler.invokeCharset(.GL, .G1, false)
+                else
+                    log.warn("unimplemented invokeCharset: {x}", .{c}),
+
+                .SI => if (@hasDecl(T, "invokeCharset"))
+                    try self.handler.invokeCharset(.GL, .G0, false)
+                else
+                    log.warn("unimplemented invokeCharset: {x}", .{c}),
             }
         }