diff --git a/src/helpers/alphabet_conversion.ts b/src/helpers/alphabet_conversion.ts
index 9ed0a1c..00ed9a1 100644
--- a/src/helpers/alphabet_conversion.ts
+++ b/src/helpers/alphabet_conversion.ts
@@ -32,3 +32,36 @@ export const convertAlphabetString = (input: string): string => {
     .filter((s) => s !== '')
     .join('')
 }
+
+/**
+ * Converts a two-digit string number (01-26) into its corresponding alphabet character (A-Z).
+ * @param numStr The two-digit numeric string to convert.
+ * @returns The alphabet character, or an empty string if invalid.
+ */
+export const numberStringToAlphabet = (numStr: string): string => {
+  if (!numStr || numStr.length !== 2) return ''
+
+  const position = parseInt(numStr, 10)
+  if (isNaN(position) || position < 1 || position > 26) return ''
+
+  // A is 65 (1 + 64)
+  return String.fromCharCode(position + 64)
+}
+
+/**
+ * Converts a string of numbers into a string of alphabet characters.
+ * Example: "010203" -> "ABC"
+ * @param input The string of numbers (must be even length).
+ * @returns The converted alphabet string.
+ */
+export const convertNumberStringToAlphabet = (input: string): string => {
+  if (!input || input.length % 2 !== 0) return ''
+
+  const result: string[] = []
+  for (let i = 0; i < input.length; i += 2) {
+    const part = input.substring(i, i + 2)
+    result.push(numberStringToAlphabet(part))
+  }
+
+  return result.join('')
+}
diff --git a/src/modules/device/queries/service.ts b/src/modules/device/queries/service.ts
index 8dd2201..72b3889 100644
--- a/src/modules/device/queries/service.ts
+++ b/src/modules/device/queries/service.ts
@@ -1,4 +1,4 @@
-import { alphabetToNumberString } from '~/helpers/alphabet_conversion'
+import { alphabetToNumberString, convertNumberStringToAlphabet } from '~/helpers/alphabet_conversion'
 import { sendQueryToThirdParty } from '../commands/command'
 import { DeviceQueryParams } from '../schema'
 
@@ -39,7 +39,7 @@ export default abstract class QueryService {
       message: 'command accepted',
       data: {
         floorName: request.data.data.floor,
-        unitNumber: request.data.data.unit,
+        unitNumber: convertNumberStringToAlphabet(request.data.data.unit),
         deviceName: request.data.data.device,
         roomName: request.data.data.room,
         deviceType: request.data.data.devType,