Dynamic QR
When the lecturer opens a roll call, the QR code is generated on the server and sent only to the lecturer’s screen. It renews at the chosen interval; students cannot work out the next code, and a photo of an old one soon becomes useless.
Short answer
DAS offers two QR modes. In “Dynamic” mode the server generates the code with a secret key and renews it every 5 to 30 seconds, 10 by default. “Static” mode keeps one code for the whole session. Students who cannot scan type an 8-character unique code into the mobile app. A lecture roll call closes within 60 minutes of opening.
QR mode
Dynamic or static, the lecturer chooses
When opening a roll call, the lecturer picks “Dynamic” or “Static” under “QR Mode” in “Advanced Settings”. Dynamic mode adds a “Refresh Rate” in seconds; in static mode a single code is valid for the whole session.
- Dynamic mode is preselected with a 10-second refresh rate
- The panel keeps the refresh rate between 5 and 30 seconds
- A static code stays valid all session, so it is less strict
Server-side code
The live code goes to the lecturer’s screen only
Each interval’s code is generated with a secret key held on the server, so students cannot work out the next one. The code is sent only to the lecturer’s screen, never to students. A photo of the projected QR works for the rest of that interval plus 10 seconds, then it is rejected.
- A signature from a photo still faces device binding and your location rule
- A student cannot sign the same roll call twice
- A student who scans an old code is told to scan the new one
Unique code
No scan? Type an 8-character code
A student who cannot scan the QR types the unique code shown on the lecturer’s screen into the mobile app. The code stays valid while the roll call is open; the lecturer can replace it with “Generate new code”, and the old one stops working.
- Look-alike characters I, O, 0 and 1 are never used
- Dashes, spaces, letter case and Turkish letters do not matter
- Code signatures go through the same device binding check
In dynamic mode the code in a photo works only for the rest of that interval plus 10 seconds, then it is rejected. A signature in that window still faces device binding and your location rule. DAS does not block photos; it keeps them useful for only a few seconds.
