https://www.swisscom.ch/en/residenti...le/combox.html
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#21#: Forward all to calls to your COMBOX®:
#61#: Forward to your COMBOX® if you don’t take the call
#67#: Forward to your COMBOX® if you are on a call.
Switching off your COMBOX®
Proceed as follows to switch off your COMBOX®:
1. Enter the respective key combination on your telephone: #21#, #61# or #67# – depending on which forwarding mode you want to switch off.
2. Press the Call button.
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Use "Swisscom Cockpit" app ( Google Play link if you don't have yet the app), right top menu -> Call settings -> Incoming Call Forward, there you can set to use or not Combox (Swisscom voicemail) for different scenarios. Don't forget to push "Save".
Same described on Swisscom site: https://www.swisscom.ch/en/residenti...le/combox.html