Here's a dumb thing I ran into this week. I have a second phone number that answers calls for me — an automated receptionist line I built recently. What I wanted was simple: if I don't pick up, or I'm already on a call, send the caller there. Not every call. Just the ones I'd otherwise miss.
So I opened Settings → Phone → Call Forwarding on my iPhone, and found exactly one option: forward everything, all the time, unconditionally. Ring my phone zero times, send it all away. That's not what I wanted, and for a moment I assumed the iPhone just couldn't do it.
It can. Apple just doesn't put it anywhere you'd ever look.
The feature exists — it lives in the dialer
Conditional call forwarding — forward only when busy, only when unanswered, only when unreachable — is a carrier feature, not a phone feature. It's been part of the GSM standard since before the iPhone existed, and your carrier almost certainly supports it. You control it by dialing special codes (they're called MMI codes, if you like trivia) straight into the Phone app, like you're calling a number made of asterisks.
The three that matter:
- Forward when busy:
*67*+ the forwarding number +#, then hit call - Forward when you don't answer:
*61*+ number +# - Forward when unreachable (phone off, no signal):
*62*+ number +#
So to send missed calls to 604-555-1234, I'd dial *61*6045551234# and press call. A confirmation screen pops up, and that's it — my phone still rings normally, and only the calls I fail to answer get redirected.
The companion codes:
- Check what's currently set:
*#61#,*#62#,*#67#(the screen shows where each condition points) - Turn one off:
##61#,##62#,##67# - Nuke all conditional forwarding at once:
##004#
One extra trick on many carriers: you can tune how long it rings before "no answer" triggers. The pattern is *61*<number>**<seconds>#, where seconds is usually a choice of 5, 10, 15, 20, 25, or 30. Not every network honors it, but it's worth trying.
The fine print I wish someone had told me first
A few things worth knowing before you start dialing asterisks:
- This is network-side. The setting lives on your carrier's equipment, not your phone. It survives reboots and works even when your phone is off — that's the whole point of the "unreachable" condition.
- Codes vary by carrier. The
*61/62/67family works on most GSM networks (which includes the big Canadian carriers and AT&T/T-Mobile in the US). Verizon historically uses its own family of codes. If a code fails, check your carrier's support page or app — some carriers now want you to toggle this in their own app instead. - Query before you overwrite. These conditions usually point at your voicemail by default — that is how voicemail works. Dial
*#61#first and note the existing number, so you can put it back when you're done experimenting. - It silently resets. SIM swaps, plan changes, port-ins, and sometimes carrier account updates can wipe conditional forwarding back to voicemail defaults. If your setup mysteriously stops working one day, this is why.
- It's per-line, not per-device. If you have dual SIM, the codes apply to whichever line is active for calls.
The slightly absurd part: none of this is new or hidden on purpose. Android exposes some of it in settings menus. Apple simply never built the UI, so on iPhone the entire feature exists only as dial codes from 1996.
While we're here: your Twilio numbers aren't a hostage situation
Same evening, different phone question. I own numbers on Twilio for my projects, and it occurred to me to ask: if I ever want to leave, can I take the numbers with me, or are they rented forever?
Answer: they're portable. You're not locked in. The process has a shape worth knowing:
- You start with the new provider, not Twilio. Ports are "pulled" by the gaining carrier — you file a port-in request with whoever you're moving to, and they handle extracting the number.
- Paperwork matters more than technology. The classic rejection is a name or address that doesn't exactly match what's on file. Ask for the account details as Twilio has them recorded, and copy them character-for-character.
- Keep the number active until the very end. Release or delete the number from your account first and it's gone for good. Twilio keeps serving the number until the gaining carrier confirms completion — that's the standard, and it prevents downtime.
- Expect weeks, not days. Standard ports typically land in one to four weeks depending on the carriers and number type. Canadian numbers port fine — the CRTC's portability rules guarantee it the same way the FCC does in the US.
- No port-out ransom. Twilio doesn't charge you to leave; the gaining side might charge a port-in fee, though many waive it.
The mental model that fixed all of this for me: your phone number is an entry in a shared industry database, not a feature of whoever bills you for it. Providers come and go. The number is yours as long as you never let it lapse.
The takeaway
Two layers, same lesson. Above the surface: the settings screens, the defaults, the impression that your options are "everything" or "nothing." One layer down: carrier codes from the nineties, port requests governed by regulators, and a lot more control than the UI ever admits to.
The iPhone can't forward your missed calls — until you ask the network directly. And the phone number you rented isn't rented at all.
What else is sitting one dial code below the surface, waiting for someone to ask the right question?
