"It's OK, All Our Guys Just Use Mobile Phones"

It's the most common thing I hear when the phone system comes up. Sometimes it's true. More often, it's true right up until someone walks into a building with no signal.

Signal is about the building, not the network

One Long Communications customer has premises next to government security offices, where mobile signal is deliberately blocked. Mobiles simply aren't an option there. That's an extreme case, but the everyday versions are common: tall buildings and basements in central London, modern coated glass, thick walls in older offices, and warehouses where metal cladding and racking stacked to the roof leave the far end of the floor a dead zone.

Wi-Fi calling helps only if the Wi-Fi is good everywhere, which in these buildings it usually isn't. Signal boosters exist, but only use ones that meet Ofcom's rules — many sold online aren't legal.

A phone that belongs to a person can't be shared

The goods-in phone, the reception phone, the supervisor's phone — these belong to a job, not a person. On mobiles alone there's no single number that rings a team, no queue, no recording, and customers end up with individual staff numbers. When someone leaves, the customer relationship can walk out with them.

A real example: a billion pounds of stock

I worked with a corporate warehouse holding around a billion pounds' worth of stock. It ran on phones: goods-in to picking, picking to dispatch, supervisors to the office, all day. Mobiles weren't realistic on that floor.

The warehouse had its own phone system, and its only route to the rest of the business was through an older, legacy phone system elsewhere, connected over ISDN.

When ISDN switches off, a site like that doesn't lose a few desk phones. It loses its connection to the rest of the business.

That setup isn't rare. Any site with more than about ten desk phones on its own system that hasn't been upgraded recently is likely to be on ISDN. My ISDN guide covers what to do about it.

Teams and phone apps don't fix it either

The next suggestion is usually "put everyone on Teams". That's fine for office staff, but it doesn't work for a seasonal or shift workforce. Seasonal workers often have no company email, laptop or Microsoft licence, a per-user licence for six weeks rarely makes sense, and nobody wants a laptop halfway up a racking aisle. They need a phone they pick up at the start of a shift and hand back at the end.

Mobiles cost more than they look

UK minutes are bundled, but international calls usually aren't, and roaming adds more. Across a team, those are the lines on the bill nobody checks. There's a newer wrinkle too: under Ofcom's tightened anti-scam rules, calls from abroad showing a UK mobile number can have their caller ID withheld unless the network can verify them. Staff calling UK customers from a trip abroad may find their number doesn't show, and the call goes unanswered.

What actually works

Landlines aren't dead; they've changed. For warehouses, factories and busy receptions the answer is usually a mix: cordless (DECT) phones running over the site's own network, which don't care about mobile signal; shared phones and team numbers for the roles that need them; and mobiles for managers and field staff, linked to the phone system so they keep a work number.

If you're not sure which camp you're in, walk the site with a phone and watch the signal bars. It's the cheapest survey you'll ever do.

Common questions

Caller ID point based on Ofcom's guidance on calls from abroad presenting UK numbers (2025–26).