diff --git a/docs/expert/infrastructure/fiber-mapping.txt b/docs/expert/infrastructure/fiber-mapping.txt
index f732133c0a085368c160c6ac6592e5a0f530c8ab..2dfa7f3999cc2786b778c767d3c61838361878be 100644
--- a/docs/expert/infrastructure/fiber-mapping.txt
+++ b/docs/expert/infrastructure/fiber-mapping.txt
@@ -337,7 +337,7 @@ S2E01-04 (GEMPILOT -- FED1469)
     GE11-X2-PLUS-SPARE-3, (empty), (empty), MTP48 breakout (*)
 
   AMC13
-    TTC -- (no label)
+    TTC -- [yellow, no label] (B top/A bottom)
     DAQ -- S2F10-18L-2
 
   (*) fiber #11 -- switch port 6:0