diff --git a/applications/apertif/commissioning/tests/verify_correlator_db_output.py b/applications/apertif/commissioning/tests/verify_correlator_db_output.py
index f6bb8e5ddec66bd12576aa0169d3e256f460d219..f6c4306adee8556ecb301e201ec095dd58af2814 100644
--- a/applications/apertif/commissioning/tests/verify_correlator_db_output.py
+++ b/applications/apertif/commissioning/tests/verify_correlator_db_output.py
@@ -30,7 +30,10 @@
    * REG_DIAG_DATA_BUFFER_OUTPUT to set the data capture at the start of a packet
    * RAM_DIAG_DATA_BUFFER_OUTPUT to read the packet data
    
-   The test verifies the read data and runs independently per PN.
+   The test verifies the read data and runs independently per PN on the correlator. The test does not access
+   the telescopes, but some --tel must be specified because --tel and --pol are used to derive the active 
+   telescope paths (TP) which will result in non-zero visibility data. The assumption is that the telescopes
+   are receiving (any noise) and outputting beamlets.
    
    Usage:
    # -v 5 or 6 for debugging
@@ -162,12 +165,10 @@ for bui in beamlets:
 
             ###################################################################
             # Verify header fields
-            unb = nr / nof_pn       # = range(N_band) = 0:15 = [0:127] / 8
-            pn  = nr % nof_pn       # = range(nof_pn) = 0:7 = [0:127] % 8
             
             # Beamlet mapping as specified in SP-062 table 6 (SC1), 9 (SC4):
             #
-            #   u  bi  dest        bu_i
+            #   u  bi  dest        bui
             #   0   0    0    FN0    0    2  ...
             #   1   0    1    FN1  256  258  ...
             #   2   0    2    FN2  512  514  ...
@@ -179,7 +180,7 @@ for bui in beamlets:
             #
             # Beamlet mapping as implemented in Apertif X due to reordered_sosi_arr wiring in node_apertif_unb1_correlator_mesh.vhd:
             #
-            #   u  bi  dest        bu_i
+            #   u  bi  dest        bui
             #   0   0    0    FN0    0    2  ...
             #   1   0    1    FN1    1    3  ...
             #   2   0    2    FN2  256  258  ...