From 7282fb51f7e4e7eaf25550f8470ca8531e4800a5 Mon Sep 17 00:00:00 2001
From: Raphael Michel <michel@rami.io>
Date: Sat, 26 Oct 2024 16:30:46 +0200
Subject: [PATCH] Add note on system IDs to docs

---
 docs/tans.rst | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/docs/tans.rst b/docs/tans.rst
index cdb5de8..f3a3eed 100644
--- a/docs/tans.rst
+++ b/docs/tans.rst
@@ -154,6 +154,13 @@ You SHOULD use this facility together with the client and dialog state restorati
     print(response.status)
     print(response.responses)
 
+System IDs
+----------
+
+During your first connection, the bank will assign your client application a "system ID" accessible
+as ``client.system_id``. Some banks require you to pass the same system ID with your next connection
+with ``FinTS3PinTanClient(..., system_id=stored_system_id)`` to avoid a TAN requirement on every login.
+(This happens automatically when using ``from_data``).
 
 Reference
 ---------