*67 to mask phone number?

Under what conditions does putting *67 in front of a number when calling it mask the calling number? I understand this does not work when calling 911 or a toll-free number, but are there other exceptions?

If an accurate answer is important to you, direct your question to your carrier as they are entity who would respect (or not) the blocking request.

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Thanks; I had no idea. I’m quite curious but it would be slow day before it became important enough for me to deal with a phone company.

In case it is a slow day, would my carrier be the MVNO (Boost Mobile) or the company that owns the towers (which I think is T-Mobile via Sprint)? And would the answer vary depending on the carrier of the party I’m calling?

Your carrier is the one you pay money to (in your case Boost Mobile). They are the ones who determine what shortcodes are available and what they do. You’re probably better off posting your question to their community forum. Here’s a post on their forum that lists all their shortcodes:

Thank you for that link. It did say *67 is available.

The reason I started this thread is that I called a business (toll number) using *67, and I have received calls from the business on what I understood to be a line with a masked number. I am certain that I did not otherwise provide the number (if only because it’s a new phone and I haven’t memorized it yet). It confused and dismayed me.

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*67 only blocks Caller ID. It does not block ANI, a different, but similar protocol.

ANI is used, for instance, so owners of a toll-free number know who is calling them. I suspect (but am not certain) that operators of PBX or VoIP switching equipment have access to ANI data as a part of the equipment’s normal reporting/logging mechanism.

If the business you called is big enough to own their switching equipment (vs. leasing someone else’s), then that might explain it.

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I’ll guess that’s what made me think that *67 didn’t work for toll-free numbers.

Sorry, I didn’t phrase that correctly. I called the mobile number of a rep for the business (preceding the rep’s number with *67), and now I’m getting calls identified as from that number. Could a mobile number be part of a PBX or VoIP of the business?

I’m not sure. What you have as a “mobile” number may actually be a PBX number or a virtual number (e.g. Google Voice) that forwards everything to a real mobile number.

Also, according to the Wikipedia article, there are companies you can pay to collect ANI data for your phone number(s). So a company that wants the data and doesn’t run their own phone switches can still get the data if they want it.

Thanks. This has been an education.

I called it a mobile number because the area code and prefix are the same as other phones that I’ve been told are mobile numbers. Of course, part of the education from this thread is that things are not always as they seem.

I suppose that would apply to cell phones numbers, too.

These days, that’s probably not a reasonable assumption. Even if blocks of numbers are initially assigned for certain purposes, the number portability laws means that number could later be transferred to a different phone of a different type at some later time.

Thanks. I had known that, but managed to purge it from my consciousness.