Your Office Line Can Forward Once. Not Twice.

Every small business in Israel knows the missed call. The phone rings while you are on a ladder, under a sink, with a patient or behind the wheel, and by the time you call back the customer has already called someone else.

The standard fix costs nothing and takes ten seconds. You dial a short code, and from then on any call you don’t pick up goes somewhere else: to a partner, a secretary, an answering service, or lately to an AI that takes a message. Then you forget about it, because forwarding is the kind of setting nobody looks at twice.

For the past two months I have been looking at it very closely, from the receiving end. And the most useful thing I have learned is a rule nobody told me when I started: a call in Israel can be forwarded once. Twice, it almost never arrives.

What travels with a forwarded call

When your phone forwards a call, the network does not just pass along the voice. In most cases it also attaches a small label that says, in effect, “this call was meant for this number, and that number sent it here.” Phone engineers call it the Diversion header. It was written up by the Internet Engineering Task Force in RFC 5806, which also describes a counter for how many times a call has been passed along, and a privacy flag that tells the next system whether it may reveal the number.

For the service on the other end, that label is everything. A human answering service, a call center or an AI receptionist answers dozens of businesses on the same few numbers. The label is how it knows that this caller wanted the locksmith and not the dental clinic, which greeting to play, and to whom the message belongs.

I know this from the inside because Onimli, the AI phone answering service my studio runs, works exactly this way. Businesses forward their unanswered calls to us, and the label tells us whose call it is.

Two hops in a month

This morning I counted every incoming call on Onimli’s numbers that our telephony provider still keeps on record: 758 calls between September 13 and October 15, 2026.

Of those, 461 arrived carrying a forwarding label. Another 297 carried none, and that group mixes people who dialed one of our numbers directly with forwarded calls whose label went missing on the way.

Here is the number that matters. Of the 461 labeled calls, 459 had been forwarded once. Two had been forwarded twice. Two calls in a month.

That would be a curiosity if nobody tried the two-step route. But it is the most natural setup in the world for a small office. The landline on the desk forwards to the owner’s mobile, and the mobile forwards to whoever answers when the owner can’t. Office, mobile, service. Each step makes sense on its own.

Earlier this month that chain failed for a business we serve. Calls to the mobile reached us fine. Calls to the office did not reach our provider at all: no ring, no record, nothing for us to answer. The first forward happened. The second never did. Both of the two-hop calls we did see, one in September and one in October, came through one and the same line. So the honest conclusion is not that it never works, but that you cannot count on it.

I can’t see inside the carriers’ exchanges, and they don’t publish how they treat a call that is already forwarded. What I can see is the result, and the result is that the second hop is where calls disappear.

Same network, different lines

The second lesson surprised me more. I assumed the label was a property of the network: Partner sends it or doesn’t, HOT sends it or doesn’t. It turned out to be messier.

When we measured in early September, calls forwarded from HOT lines carried the label 327 times out of 334. Calls from 019 carried it 20 times out of 21. A Rami Levy line we tested in August forwarded fine, and every call arrived with no label at all.

Partner was the puzzle. Three Partner lines never delivered a label, on any call. Then, in October, we checked a fourth Partner line, and every one of its seven forwarded calls had arrived with the label intact. Same network, opposite behavior. Whatever decides it sits on the individual line, not on the company’s name.

My own two phones are on HOT, which is exactly why I didn’t see any of this at first. Every test I ran from my own desk worked perfectly.

When the label is missing

A missing label is not a minor technical detail. It means the service on the other end has to guess, and a wrong guess is worse than no answer.

We learned that the hard way. For a while, a call with no label on our main number was treated as someone calling Onimli directly. So a few callers of a business whose carrier stripped the label heard our own greeting, the one meant for people asking about our service, instead of the business they had dialed. It was our mistake, not the carrier’s, and we fixed it the only safe way: a business on a line that may lose the label now gets a phone number of its own to forward to, so no label is needed. An unproven carrier is treated as unsafe until a real call shows otherwise.

I made a smaller mistake too, the kind anyone could make. I wrote a customer the code to check a forwarding setting, and typed #61#. On most phones that code doesn’t check anything. It switches the forwarding off.

What to check before you trust a forward

None of this means forwarding is broken. Hundreds of calls a month reach us exactly as intended. It means a forward deserves the same ten minutes of testing you would give a new card reader. Small Israeli studios such as Achiya Automation, which builds phone and WhatsApp automation for local businesses, end up doing this testing for a living; you can do it yourself in an afternoon.

Use one hop. If the office line should end up with an answering service, forward the office line straight to the service, not through your mobile. If you want your mobile to ring first, ask your carrier whether the office line can ring your mobile and then send unanswered calls on; that is a different service from a chain of forwards.

Test from a phone that isn’t yours. Ask a friend on another network to call the office number, not your mobile, and let it ring out. Then ask the service what they saw and which greeting played. A test from your own mobile proves very little.

Ask what happens without the label. Any provider who answers calls for many businesses should be able to tell you, in one sentence, what they do when a forwarded call arrives with no label. If the answer is a guess, ask for a dedicated number.

Check your codes, carefully. On most Israeli mobiles, a code starting with *# checks a setting, a code starting with ## erases it, and #61# turns off forwarding when you don’t answer. Write down what you dialed.

Forwarding was built for a world where a call went from one phone to one other phone. Small businesses now stack them, one helpful step at a time, and nobody tells them that the third phone in the chain may never ring.

If you forward your calls, how many phones does a call pass through before someone answers, and have you ever tested it from a number that isn’t yours?

Achiya Cohen runs Achiya Automation, a small Israeli studio that builds phone and WhatsApp automation for businesses, including the AI answering service Onimli.