--- a/doc/ADM-PIN-numbering	Tue Mar 23 23:30:00 2021 +0000
+++ b/doc/ADM-PIN-numbering	Wed Mar 24 00:31:45 2021 +0000
@@ -85,3 +85,19 @@
 * Looking at Grcard's own documentation (see doc/vendor/grcard2-person-script),
   one can see that Grcard engineers refer to them as ADM2 and ADM8, following
   the numbering shift explained earlier in this article.
+
+Sysmocom USIM/ISIM cards
+========================
+
+All UICC/USIM/ISIM cards we know of (made by Sysmocom and others) have just one
+administrative PIN which they call ADM1, and in the UICC protocol this ADM1 PIN
+is entered with a VERIFY PIN command with P2=0x0A.  If a UICC-native card also
+allows ADM1 authentication in a GSM 11.11 SIM protocol session, then the
+corresponding extended VERIFY CHV command will also use P2=0x0A.
+
+Because these cards implement the classic GSM 11.11 SIM protocol only as a
+backward compatibility mode, rather than native, there is no universal agreement
+regarding ADM access level codes returned in SELECT responses for EFs in the
+classic SIM protocol: sysmoUSIM-SJS1 cards return ADM5, whereas sysmoISIM-SJA2
+cards return ADM10 - both numbers are per FC SIM tools numbering convention of
+ADM4 through ADM14.