diff --git a/src/components/Canvas/BarcodeObject.tsx b/src/components/Canvas/BarcodeObject.tsx
index 4864c430..d4af854e 100644
--- a/src/components/Canvas/BarcodeObject.tsx
+++ b/src/components/Canvas/BarcodeObject.tsx
@@ -66,7 +66,11 @@ export function BarcodeObject({
       bwipjs.toCanvas(canvas, opts as unknown as Parameters<typeof bwipjs.toCanvas>[1]);
       barcodeCanvas = canvas;
     } catch (e) {
-      errorMsg = e instanceof Error ? e.message : String(e);
+      const raw = e instanceof Error ? e.message : String(e);
+      // bwip-js prefixes its errors like `bwip-js: bwipp.code39badCharacter: ...`
+      // Strip the library/identifier head so the placeholder shows only the
+      // human-readable reason.
+      errorMsg = raw.replace(/^bwip-js:\s*/i, '').replace(/^bwipp\.[^:]+:\s*/i, '');
     }
   }
 
@@ -589,9 +593,13 @@ export function BarcodeObject({
       <Text
         x={6}
         y={6}
+        width={fbW - 12}
+        height={fbH - 12}
+        wrap="word"
+        ellipsis
         text={errorMsg ? `⚠ ${errorMsg}` : obj.type}
         fontSize={Math.max(dotsToPx(10, scale, dpmm), 8)}
-        fill="#374151"
+        fill={errorMsg ? "#b91c1c" : "#374151"}
       />
     </Group>
   );
diff --git a/src/components/Canvas/bwipHelpers.ts b/src/components/Canvas/bwipHelpers.ts
index cf20ac20..aee1ab7e 100644
--- a/src/components/Canvas/bwipHelpers.ts
+++ b/src/components/Canvas/bwipHelpers.ts
@@ -204,7 +204,15 @@ export function buildBwipOptions(
     case "codabar":
     case "plessey": {
       const p = obj.props;
-      opts = { bcid, text: p.content || "0", scale: scale1D, height: 10 };
+      // Code39/Codabar/Plessey only encode uppercase letters. Zebra firmware
+      // (and Labelary) silently uppercase lowercase input; bwip-js does not and
+      // throws instead, which would crash the canvas for any imported ZPL with
+      // lowercase content. Uppercase here so the lib matches firmware behaviour
+      // without rewriting the user's source.
+      const needsUpper = obj.type === "code39" || obj.type === "codabar" || obj.type === "plessey";
+      const raw = p.content || "0";
+      const text = needsUpper ? raw.toUpperCase() : raw;
+      opts = { bcid, text, scale: scale1D, height: 10 };
       break;
     }
     case "msi": {
@@ -221,9 +229,10 @@ export function buildBwipOptions(
     }
     case "logmars": {
       const p = obj.props;
+      // LOGMARS is a Code39 subset; same uppercase rule applies.
       opts = {
         bcid,
-        text: p.content || "0",
+        text: (p.content || "0").toUpperCase(),
         scale: scale1D,
         height: 10,
         includecheck: true,
diff --git a/src/registry/aztec.tsx b/src/registry/aztec.tsx
index dddf0f66..b759d4c7 100644
--- a/src/registry/aztec.tsx
+++ b/src/registry/aztec.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from "../types/ObjectType";
 import { useT } from "../lib/useT";
 import { inputCls, labelCls } from "../components/Properties/styles";
-import { fieldPos } from "./zplHelpers";
+import { fieldPos, fdField } from "./zplHelpers";
 
 export interface AztecProps {
   content: string;
@@ -27,7 +27,7 @@ export const aztec: ObjectTypeDefinition<AztecProps> = {
     return [
       fieldPos(obj),
       `^B0N,${p.magnification},N,N,N,N`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ].join("");
   },
 
diff --git a/src/registry/barcode1d.tsx b/src/registry/barcode1d.tsx
index 6ee04215..7c09932f 100644
--- a/src/registry/barcode1d.tsx
+++ b/src/registry/barcode1d.tsx
@@ -1,8 +1,9 @@
 import type { ObjectTypeDefinition, ObjectGroup, LabelObjectBase } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { commitHeightTransform } from './transformHelpers';
+import { filterContent, type ContentSpec } from './contentSpec';
 
 export interface Barcode1DProps {
   content: string;
@@ -16,7 +17,6 @@ interface Barcode1DConfig {
   label: string;
   icon: string;
   defaultContent: string;
-  contentMaxLength?: number;
   hasCheckDigit: boolean;
   /** Build the ZPL barcode command (e.g. `^BUN,100,Y,N,N`). */
   zplCommand: (p: Barcode1DProps) => string;
@@ -34,6 +34,8 @@ interface Barcode1DConfig {
   heightLocked?: boolean;
   /** See {@link ObjectTypeDefinition.interpretationLocked}. */
   interpretationLocked?: boolean;
+  /** Restrict allowed input characters; see {@link ContentSpec}. */
+  contentSpec?: ContentSpec;
 }
 
 interface BarcodeLocale {
@@ -77,7 +79,7 @@ export function createBarcode1D(config: Barcode1DConfig): ObjectTypeDefinition<B
         byCmd,
         fieldPos(obj),
         config.zplCommand(p),
-        `^FD${p.content}^FS`,
+        fdField(p.content),
       ].filter(Boolean).join('');
     },
 
@@ -92,9 +94,9 @@ export function createBarcode1D(config: Barcode1DConfig): ObjectTypeDefinition<B
             <input
               className={inputCls}
               value={p.content}
-              maxLength={config.contentMaxLength}
+              maxLength={config.contentSpec?.maxLength}
               placeholder={loc.placeholder}
-              onChange={(e) => onChange({ content: e.target.value })}
+              onChange={(e) => onChange({ content: filterContent(e.target.value, config.contentSpec) })}
             />
           </div>
 
diff --git a/src/registry/codabar.tsx b/src/registry/codabar.tsx
index 58edac8a..7a3efefb 100644
--- a/src/registry/codabar.tsx
+++ b/src/registry/codabar.tsx
@@ -8,6 +8,7 @@ export const codabar = createBarcode1D({
   hasCheckDigit: true,
   localeKey: "codabar",
   group: 'code-1d',
+  contentSpec: { charset: '0-9A-Da-d\\-$:/.+' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     const check = p.checkDigit ? "Y" : "N";
diff --git a/src/registry/codablock.tsx b/src/registry/codablock.tsx
index 4769322d..70af76dd 100644
--- a/src/registry/codablock.tsx
+++ b/src/registry/codablock.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from "../types/ObjectType";
 import { useT } from "../lib/useT";
 import { inputCls, labelCls } from "../components/Properties/styles";
-import { fieldPos } from "./zplHelpers";
+import { fieldPos, fdField } from "./zplHelpers";
 import { commitStacked2DTransform } from "./transformHelpers";
 
 export interface CodablockProps {
@@ -32,7 +32,7 @@ export const codablock: ObjectTypeDefinition<CodablockProps> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^BBN,${p.rowHeight},${p.securityLevel}`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ]
       .filter(Boolean)
       .join("");
diff --git a/src/registry/code11.tsx b/src/registry/code11.tsx
index 3a87fe06..70d02f6c 100644
--- a/src/registry/code11.tsx
+++ b/src/registry/code11.tsx
@@ -8,6 +8,7 @@ export const code11 = createBarcode1D({
   hasCheckDigit: true,
   localeKey: "code11",
   group: 'code-1d',
+  contentSpec: { charset: '0-9\\-' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     const check = p.checkDigit ? "Y" : "N";
diff --git a/src/registry/code128.tsx b/src/registry/code128.tsx
index dd3a8dd8..4391724c 100644
--- a/src/registry/code128.tsx
+++ b/src/registry/code128.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { commitHeightTransform } from './transformHelpers';
 
 export interface Code128Props {
@@ -35,7 +35,7 @@ export const code128: ObjectTypeDefinition<Code128Props> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^BCN,${p.height},${interp},N,${check}`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ].filter(Boolean).join('');
   },
 
diff --git a/src/registry/code39.tsx b/src/registry/code39.tsx
index 78461428..114a5143 100644
--- a/src/registry/code39.tsx
+++ b/src/registry/code39.tsx
@@ -1,8 +1,11 @@
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { commitHeightTransform } from './transformHelpers';
+import { filterContent, type ContentSpec } from './contentSpec';
+
+const code39Spec: ContentSpec = { charset: '0-9A-Za-z\\-. $/+%' };
 
 export interface Code39Props {
   content: string;
@@ -35,7 +38,7 @@ export const code39: ObjectTypeDefinition<Code39Props> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^B3N,${check},${p.height},${interp},N`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ].filter(Boolean).join('');
   },
 
@@ -49,7 +52,7 @@ export const code39: ObjectTypeDefinition<Code39Props> = {
           <input
             className={inputCls}
             value={p.content}
-            onChange={(e) => onChange({ content: e.target.value })}
+            onChange={(e) => onChange({ content: filterContent(e.target.value, code39Spec) })}
           />
         </div>
 
diff --git a/src/registry/contentSpec.ts b/src/registry/contentSpec.ts
new file mode 100644
index 00000000..f33940bb
--- /dev/null
+++ b/src/registry/contentSpec.ts
@@ -0,0 +1,30 @@
+/**
+ * Per-symbology content rules. Applied on input so the canvas preview
+ * (bwip-js) does not throw on characters the renderer rejects.
+ *
+ * Case normalisation is intentionally not done here: the source ZPL
+ * is preserved verbatim, and `bwipHelpers` uppercases at the lib call
+ * site for the symbologies that require it.
+ */
+export interface ContentSpec {
+  /** Character-class body (no surrounding `[]`), e.g. `0-9` or `0-9A-Z\\-. $/+%`. */
+  charset: string;
+  maxLength?: number;
+}
+
+const rejectCache = new WeakMap<ContentSpec, RegExp>();
+
+function rejectPattern(spec: ContentSpec): RegExp {
+  let re = rejectCache.get(spec);
+  if (!re) {
+    re = new RegExp(`[^${spec.charset}]`, 'g');
+    rejectCache.set(spec, re);
+  }
+  return re;
+}
+
+export function filterContent(raw: string, spec?: ContentSpec): string {
+  if (!spec) return raw;
+  const filtered = raw.replace(rejectPattern(spec), '');
+  return spec.maxLength ? filtered.slice(0, spec.maxLength) : filtered;
+}
diff --git a/src/registry/datamatrix.tsx b/src/registry/datamatrix.tsx
index 25e5d810..3eb583f0 100644
--- a/src/registry/datamatrix.tsx
+++ b/src/registry/datamatrix.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { clamp } from './transformHelpers';
 
 export interface DataMatrixProps {
@@ -30,7 +30,7 @@ export const datamatrix: ObjectTypeDefinition<DataMatrixProps> = {
     return [
       fieldPos(obj),
       `^BXN,${p.dimension},${p.quality}`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ].join('');
   },
 
diff --git a/src/registry/ean13.tsx b/src/registry/ean13.tsx
index cc0bd197..e9244a8f 100644
--- a/src/registry/ean13.tsx
+++ b/src/registry/ean13.tsx
@@ -1,8 +1,11 @@
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { commitHeightTransform } from './transformHelpers';
+import { filterContent, type ContentSpec } from './contentSpec';
+
+const ean13Spec: ContentSpec = { charset: '0-9', maxLength: 12 };
 
 export interface Ean13Props {
   content: string;        // 12 digits — ZPL appends the check digit automatically
@@ -32,7 +35,7 @@ export const ean13: ObjectTypeDefinition<Ean13Props> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^BEN,${p.height},${interp},N`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ].filter(Boolean).join('');
   },
 
@@ -48,7 +51,7 @@ export const ean13: ObjectTypeDefinition<Ean13Props> = {
             value={p.content}
             maxLength={12}
             placeholder={t.registry.ean13.placeholder}
-            onChange={(e) => onChange({ content: e.target.value })}
+            onChange={(e) => onChange({ content: filterContent(e.target.value, ean13Spec) })}
           />
         </div>
 
diff --git a/src/registry/ean8.tsx b/src/registry/ean8.tsx
index b8756853..64a6b26e 100644
--- a/src/registry/ean8.tsx
+++ b/src/registry/ean8.tsx
@@ -5,10 +5,10 @@ export const ean8 = createBarcode1D({
   label: 'EAN-8',
   icon: 'E8',
   defaultContent: '1234567',
-  contentMaxLength: 7,
   hasCheckDigit: false,
   localeKey: 'ean8',
   group: 'code-1d',
+  contentSpec: { charset: '0-9', maxLength: 7 },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
     return `^B8N,${p.height},${interp},N`;
diff --git a/src/registry/gs1databar.tsx b/src/registry/gs1databar.tsx
index ac1727a1..80a02376 100644
--- a/src/registry/gs1databar.tsx
+++ b/src/registry/gs1databar.tsx
@@ -8,6 +8,7 @@ export const gs1databar = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "gs1databar",
   group: 'code-1d',
+  contentSpec: { charset: '0-9' },
   // GS1 Databar Omnidirectional has a symbology-fixed height; Zebra/Labelary
   // ignore the ^BR height parameter for this variant. Disabling resize and the
   // height input keeps the designer honest about what affects the print.
diff --git a/src/registry/industrial2of5.tsx b/src/registry/industrial2of5.tsx
index 04c9a129..43647221 100644
--- a/src/registry/industrial2of5.tsx
+++ b/src/registry/industrial2of5.tsx
@@ -8,6 +8,7 @@ export const industrial2of5 = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "industrial2of5",
   group: 'code-1d',
+  contentSpec: { charset: '0-9' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     return `^BIN,${p.height},${interp},N`;
diff --git a/src/registry/interleaved2of5.tsx b/src/registry/interleaved2of5.tsx
index af8f5805..8006a911 100644
--- a/src/registry/interleaved2of5.tsx
+++ b/src/registry/interleaved2of5.tsx
@@ -8,6 +8,7 @@ export const interleaved2of5 = createBarcode1D({
   hasCheckDigit: true,
   localeKey: 'interleaved2of5',
   group: 'code-1d',
+  contentSpec: { charset: '0-9' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
     const check = p.checkDigit ? 'Y' : 'N';
diff --git a/src/registry/logmars.tsx b/src/registry/logmars.tsx
index 5e47e5a3..583ccef3 100644
--- a/src/registry/logmars.tsx
+++ b/src/registry/logmars.tsx
@@ -8,6 +8,7 @@ export const logmars = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "logmars",
   group: 'code-1d',
+  contentSpec: { charset: '0-9A-Za-z\\-. $/+%' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     return `^BLN,${p.height},${interp}`;
diff --git a/src/registry/micropdf417.tsx b/src/registry/micropdf417.tsx
index e7cd20c0..c44214d2 100644
--- a/src/registry/micropdf417.tsx
+++ b/src/registry/micropdf417.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from "../types/ObjectType";
 import { useT } from "../lib/useT";
 import { inputCls, labelCls } from "../components/Properties/styles";
-import { fieldPos } from "./zplHelpers";
+import { fieldPos, fdField } from "./zplHelpers";
 import { commitStacked2DTransform } from "./transformHelpers";
 
 export interface MicroPdf417Props {
@@ -32,7 +32,7 @@ export const micropdf417: ObjectTypeDefinition<MicroPdf417Props> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^BFN,${p.rowHeight},${p.mode}`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ]
       .filter(Boolean)
       .join("");
diff --git a/src/registry/msi.tsx b/src/registry/msi.tsx
index 82998c10..f3f1f0e1 100644
--- a/src/registry/msi.tsx
+++ b/src/registry/msi.tsx
@@ -8,6 +8,7 @@ export const msi = createBarcode1D({
   hasCheckDigit: true,
   localeKey: "msi",
   group: 'code-1d',
+  contentSpec: { charset: '0-9' },
   // MSI standard specifies a 2:1 wide:narrow ratio, which bwip-js hardcodes
   // internally. ZPL ^BY defaults to 3.0, so we must override to keep canvas
   // and Labelary preview in sync.
diff --git a/src/registry/pdf417.tsx b/src/registry/pdf417.tsx
index 39a07f4f..9a22d7ef 100644
--- a/src/registry/pdf417.tsx
+++ b/src/registry/pdf417.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from "../types/ObjectType";
 import { useT } from "../lib/useT";
 import { inputCls, labelCls } from "../components/Properties/styles";
-import { fieldPos } from "./zplHelpers";
+import { fieldPos, fdField } from "./zplHelpers";
 import { commitStacked2DTransform } from "./transformHelpers";
 
 export interface Pdf417Props {
@@ -33,7 +33,7 @@ export const pdf417: ObjectTypeDefinition<Pdf417Props> = {
       `^BY${p.moduleWidth}`,
       fieldPos(obj),
       `^B7N,${p.rowHeight},${p.securityLevel},${p.columns},,,`,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
     ]
       .filter(Boolean)
       .join("");
diff --git a/src/registry/planet.tsx b/src/registry/planet.tsx
index d8185236..f1c58520 100644
--- a/src/registry/planet.tsx
+++ b/src/registry/planet.tsx
@@ -8,6 +8,7 @@ export const planet = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "planet",
   group: 'code-postal',
+  contentSpec: { charset: '0-9' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     return `^B5N,${p.height},${interp},N`;
diff --git a/src/registry/plessey.tsx b/src/registry/plessey.tsx
index 99385eb7..e592f98e 100644
--- a/src/registry/plessey.tsx
+++ b/src/registry/plessey.tsx
@@ -8,6 +8,7 @@ export const plessey = createBarcode1D({
   hasCheckDigit: true,
   localeKey: "plessey",
   group: 'code-1d',
+  contentSpec: { charset: '0-9A-Fa-f' },
   // Plessey uses 2:1 wide:narrow ratio (same as MSI); override ZPL default of 3.0
   byRatio: 2,
   zplCommand: (p) => {
diff --git a/src/registry/postal.tsx b/src/registry/postal.tsx
index b9949ba7..0179d435 100644
--- a/src/registry/postal.tsx
+++ b/src/registry/postal.tsx
@@ -8,6 +8,7 @@ export const postal = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "postal",
   group: 'code-postal',
+  contentSpec: { charset: '0-9' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     // ^BZ{orientation},{height},{interp},{startStop}
diff --git a/src/registry/qrcode.tsx b/src/registry/qrcode.tsx
index 29d75887..022ede6d 100644
--- a/src/registry/qrcode.tsx
+++ b/src/registry/qrcode.tsx
@@ -1,7 +1,7 @@
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { clamp } from './transformHelpers';
 
 export interface QrCodeProps {
@@ -30,7 +30,7 @@ export const qrcode: ObjectTypeDefinition<QrCodeProps> = {
     return [
       fieldPos(obj),
       `^BQN,2,${p.magnification}`,
-      `^FD${p.errorCorrection}A,${p.content}^FS`,
+      fdField(`${p.errorCorrection}A,${p.content}`),
     ].join('');
   },
 
diff --git a/src/registry/serial.tsx b/src/registry/serial.tsx
index d65ad2ac..18ec0ac0 100644
--- a/src/registry/serial.tsx
+++ b/src/registry/serial.tsx
@@ -2,6 +2,9 @@ import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
 import { fieldPos } from './zplHelpers';
+import { filterContent, type ContentSpec } from './contentSpec';
+
+const serialSpec: ContentSpec = { charset: '0-9A-Za-z' };
 
 export interface SerialProps {
   content: string;
@@ -48,7 +51,7 @@ export const serial: ObjectTypeDefinition<SerialProps> = {
             <input
               className={inputCls}
               value={p.content}
-              onChange={(e) => onChange({ content: e.target.value })}
+              onChange={(e) => onChange({ content: filterContent(e.target.value, serialSpec) })}
             />
           </div>
           <div className="flex flex-col gap-1">
diff --git a/src/registry/standard2of5.tsx b/src/registry/standard2of5.tsx
index 37d7d835..67b95c12 100644
--- a/src/registry/standard2of5.tsx
+++ b/src/registry/standard2of5.tsx
@@ -8,6 +8,7 @@ export const standard2of5 = createBarcode1D({
   hasCheckDigit: false,
   localeKey: "standard2of5",
   group: 'code-1d',
+  contentSpec: { charset: '0-9' },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? "Y" : "N";
     return `^BJN,${p.height},${interp},N`;
diff --git a/src/registry/text.tsx b/src/registry/text.tsx
index 83012f7f..863b2ac5 100644
--- a/src/registry/text.tsx
+++ b/src/registry/text.tsx
@@ -2,7 +2,7 @@ import { useRef, useState, useCallback } from 'react';
 import type { ObjectTypeDefinition } from '../types/ObjectType';
 import { useT } from '../lib/useT';
 import { inputCls, labelCls } from '../components/Properties/styles';
-import { fieldPos } from './zplHelpers';
+import { fieldPos, fdField } from './zplHelpers';
 import { getFont, getAllFonts, loadFontFile } from '../lib/fontCache';
 import { useFontCacheVersion } from '../hooks/useFontCacheVersion';
 
@@ -50,7 +50,7 @@ export const text: ObjectTypeDefinition<TextProps> = {
       fieldPos(obj),
       fontCmd,
       fbCmd,
-      `^FD${p.content}^FS`,
+      fdField(p.content),
       p.reverse ? '^LRN' : '',
     ].filter(Boolean).join('');
   },
diff --git a/src/registry/upca.tsx b/src/registry/upca.tsx
index f377414d..fd6c7433 100644
--- a/src/registry/upca.tsx
+++ b/src/registry/upca.tsx
@@ -5,10 +5,10 @@ export const upca = createBarcode1D({
   label: 'UPC-A',
   icon: 'UPC',
   defaultContent: '01234567890',
-  contentMaxLength: 11,
   hasCheckDigit: false,
   localeKey: 'upca',
   group: 'code-1d',
+  contentSpec: { charset: '0-9', maxLength: 11 },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
     return `^BUN,${p.height},${interp},N,N`;
diff --git a/src/registry/upce.tsx b/src/registry/upce.tsx
index 0002b654..f1ea270b 100644
--- a/src/registry/upce.tsx
+++ b/src/registry/upce.tsx
@@ -5,10 +5,10 @@ export const upce = createBarcode1D({
   label: 'UPC-E',
   icon: 'UPE',
   defaultContent: '012345',
-  contentMaxLength: 6,
   hasCheckDigit: false,
   localeKey: 'upce',
   group: 'code-1d',
+  contentSpec: { charset: '0-9', maxLength: 6 },
   zplCommand: (p) => {
     const interp = p.printInterpretation ? 'Y' : 'N';
     return `^B9N,${p.height},${interp},N`;
diff --git a/src/registry/zplHelpers.ts b/src/registry/zplHelpers.ts
index e4f1483b..e0008520 100644
--- a/src/registry/zplHelpers.ts
+++ b/src/registry/zplHelpers.ts
@@ -5,3 +5,25 @@ export function fieldPos(obj: LabelObjectBase): string {
   const cmd = obj.positionType === 'FT' ? 'FT' : 'FO';
   return `^${cmd}${obj.x},${obj.y}`;
 }
+
+const FH_DELIM = '_';
+const NEEDS_FH = /[\^~]/;
+
+function hex(ch: string): string {
+  return FH_DELIM + ch.charCodeAt(0).toString(16).toUpperCase().padStart(2, '0');
+}
+
+/**
+ * Build a `^FD…^FS` block, hex-escaping `^` and `~` so user content cannot
+ * smuggle ZPL commands. Caret/tilde are the format and command prefixes; if a
+ * label payload contains them raw, the firmware will reinterpret them as new
+ * commands and the field truncates or the whole block becomes malformed.
+ *
+ * When escape is needed we prefix `^FH_` and hex-encode `^`, `~`, and the
+ * delimiter `_` itself (so literal underscores in the payload survive).
+ */
+export function fdField(payload: string): string {
+  if (!NEEDS_FH.test(payload)) return `^FD${payload}^FS`;
+  const escaped = payload.replace(/[\^~_]/g, hex);
+  return `^FH${FH_DELIM}^FD${escaped}^FS`;
+}