diff --git a/src/ext/lib/comms/CommsServer.ts b/src/ext/lib/comms/CommsServer.ts
index 3db1fe6..1c77452 100644
--- a/src/ext/lib/comms/CommsServer.ts
+++ b/src/ext/lib/comms/CommsServer.ts
@@ -13,9 +13,9 @@ class CommsServer {
 
 
   ports: {
-    [tab: string | number] : {
-      [frame: string | number] : {
-        [port: string | number]: any
+    [tab: string] : {
+      [frame: string] : {
+        [port: string]: any
       }
     }
   } = {};