If I am not mistaken, I managed to make anonymous calls in the past by prefixing the number with #31#. On the other hand, I could be wrong because it does not work if I try it now.
I get an ‘unknown number’ error.
If I dial #31# separately, I end up in a blank screen titled ‘USSD’ that has a cancel button that changes into a close button (or the other way round, I forgot).
In the settings there is no option for making your calls anonymous. Most other phones do have this options, I think
USSD codes will work if your carrier still supports them. And the USSD code what changes the call to “anonymous” might be different with different carriers.
Unfortunately USSD codes are not necessary in 99,9999% cases in 2024 so they are not anymore universal approach to this. And that is one reason why they don’t work with my carrier :S. I hope you have better luck because that is the option what you have with linux mobile
Per this table, that’s correct and it should work globally (anywhere where GSM or its successors is used).
The web page notes that they are not technically USSD codes.
There is other discussion in this forum of this kind of functionality.
I think the key point from the above page is:
they are standardized so they are the same on every GSM phone. They are interpreted by the handset first before a corresponding command (not the code itself) is sent to the network. These codes might not always work when using an AT interface; there are standard AT commands defined for each of these actions instead.
I would say that the support is incomplete or missing on the handset (Librem 5, here) and/or the modem. I have no idea which ones are supposed to work and which ones are not, as at today, and whether the commands that are sent to the network are network-specific (and hence require configuration / coding for each network).
Minor gripe:
Depends on whom you want to be anonymous to. Your call may be anonymous (Calling Line Id - CLI - not sent) to the party that you call. Your call will not be anonymous to any network operator who is involved in the call, or to any spying government, or to any coercive government etc.
You will also note that over the years many people have said that they don’t answer calls when the CLI is suppressed. (For example, a person only answers the call if the CLI identifies a known contact.) So there is a trade-off to be made, as the caller.
Never had any problems with calls being unanswered because of calling anonymously.
Even gouvernments make use of calling you anonymously.
But when this issue would be fixed, one could easily have the means of deciding to make this choise per call.
BTW: By using modem-manager-gui you can easily store these codes and use them later again. I do this once in a while to test if updates have resolved the issue.
In Germany near all phone companies and offices suppress this because of hundreds of callers every month who try to sell You “newest-secret-outstanding-methods” to maximize Your money with investing in their products on stock exchange
Or investing in brand-new technologies in renewable energy and much more
I put the question to our service desk earlier. Or actually I told them I wanted permission to make calls outside our organisation via Teams, because I did not want to compromise my privacy by using a private phone that does not manage to make anonymous calls.
One hopeful employee obviously thought he would be able to help out a poor computer illiterate: he asked what model phone I had.
Very curious what he is going to come up with…
This problem we cannot have in germany. Using a private phone in office will let explode a bunch of privay rules about safety and compromitting customers addresses on a private phone…
Our DSGVO is v e r y clear in this. It is a NoGo with private phones using fur business use. This can only be allowed if You use a mobile device management SW which absolutely safe run 2 different environments (private use and office use) on Your phone. And any data exchange between them ist not allowed.
It all depends on what you are trying to avoid:
Getting harrased by let’s say some sales guy or avoiding sharing your phone number with unknown third parties who may collect phone numbers and next sell them to data brokers who sell them to sales guys.
As a result you could getting calls from those sales guys.
So far I’m not being called by them. Maybe me dailing anonymously is the cause of that. Who knows?
I don’t judge people who have problems with anonymous callers, but please do not judge me (or others) for choosing not to share the number.
We all have our (good) reasons to act the way we do.
You misunderstand me. I support anonymous calling. I oppose government calls. It’s about choosing not to answer anonymous calls, but not about being prohibited from making them.