Ascom/Swissvoice DECT Phone Hacking

Or: How to enable the “Support” menu of Ascom/Swissvoice DECT handsets…

While playing around with the DECT base station built into my new AVM FRITZ!Box Fon WLAN 7270 I just got a day ago I actually managed to get the handset into an endless loop signing on to the base station, failing, beeping and starting all over. I remembered having read about a support menu built into the handsets of these phones and after a little trial and error managed to revive my phone by disabling DECT in the FRITZ!Box base station (to stop the endless looping) and clearing the phone’s registration via the handset reset built into the support menu.

So, how does one activate the support menu? Enter the ordinary menu (on my Eurit 535 that means pressing the right-hand side soft-key) and (blindly) enter the following key sequence: 0#00#. Hit the “C” key to leave the menu and press the menu soft-key again. Et voilà: There goes the support menu.

Disclaimer: Use the support menu at your own risk - using some of its features may permanently brick your handset.

Entering the menu will bring up the following menu items (HS = handset, BS = base station):

  • Reset HS-PIN

  • Reset HS ex Dir. (reset handset, but leave phone book in place)

  • Reset HD Total (do a complete handset factory reset)

  • Set Start Menu (?)

  • Reset Sys-PIN

  • Reset BS (reset base station?)

  • Reset BS Total (?)

  • TBR6 Mode 1 HS (?)

  • TBR6 Mode 2 HS (?)

  • TBR10 Mode HS (?)

  • Setup Test Bear. (?)

  • Crash Dump HS

  • Crash Dump BS

  • Prüf.tech.dat.HS (various HS-related firmware and hardware information)

  • Prüf.tech.dat.BS (various BS-related firmware and hardware information)

  • Download P&P (?)

  • NES on/off (?)

I did not touch most of these as some sound quite low-level and I do not want to end up with a bricked handset.

BTW, to disable the support menu, just turn the handset off and on again.