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Guide · 2026-07-23 · 5 min read

Setting up call forwarding. And the limit nobody mentions.

Setting it up takes thirty seconds. The real question comes after: who picks up at the other end?

In 40 seconds

On mobile, you forward calls with a GSM code: **21*target number# turns on unconditional forwarding, ##21# switches it off. On a landline, the provider's web portal or phone menu does the job. The catch: forwarded isn't answered.

Call forwarding takes no time at all. On your mobile you type a short code, on a landline you click through the provider's portal. The hard part comes after, and almost nobody talks about it: forwarding only moves the call. It doesn't answer it.

Call forwarding on mobile: the GSM codes

On a mobile phone, forwarding runs on GSM codes that work regardless of network. You dial them like a phone number and hit call.

  • Forward everything: dial **21*target number# and call it. Every call now goes straight to the target number.
  • Only when engaged: **67*target number#. Only when unreachable: **62*target number#. Only when you don't answer: **61*target number#.
  • Check what's active: dial *#21#. Switch everything off: ##21#.

These are GSM standard codes, not some carrier trick. Once you know them, you can set up forwarding in a lift, no menu, no helpline.

Call forwarding on a landline

On a landline, the method depends on your line. With a standard provider account, you set forwarding up in your online account; with a router-based system such as a BT Hub or similar, it's under phone settings in the web interface. The principle is the same everywhere: enter the target number, choose the condition (always, when engaged, when unanswered), save. The only thing that matters is that the target number is actually reachable.

And here's exactly where the problem sits

You forward calls because you can't pick up right now. Out on site, at the second shop, over the weekend. But on the other end sits, often enough, the same person who had no time to begin with. Or voicemail. Voicemail doesn't book an appointment, doesn't answer a question, and doesn't call back. It just stores.

The call you don't pick up isn't neutral. Someone who rings outside opening hours and reaches nobody tries the next business. Once. And stays there. Forwarding to a number nobody's watching just shifts that risk. It doesn't solve it.

The forwarding that actually picks up

There's one case where forwarding keeps its promise: when someone's on the other end actually having the conversation. That's exactly what we built Rinqo for. You forward the calls you can't take to your phone agent. It picks up, answers questions from the company knowledge you've given it, books appointments straight into the calendar, and sends you a summary by email after every call. Round the clock, weekends included.

Technically, it's still call forwarding, you already know the steps. What changes is what happens next. Instead of voicemail that stores, a conversation that moves things forward. And because response latency stays under 800 milliseconds, hardly anyone on the other end notices a gap. The legally required AI disclosure is built into the start of every call.

If you only need forwarding for your lunch break, the GSM code above is enough. If calls regularly slip through, and jobs with them, the question isn't where you forward to. It's who picks up.

Sven Pflüger

Sven Pflüger

Founder & CEO, Rinqo

Sven builds Rinqo from a simple observation: most AI tools are designed in San Francisco and sold in Berlin. The workshop in the Black Forest, the veterinary practice in Salzburg, the family hotel in Tyrol get software that doesn't speak their language. Rinqo flips that. On European servers, set up in ten minutes, in twenty languages. With templates built by the industries themselves.

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