How to get 400 numbering for legal telemarketing

To operate with 400 numbering you need three things: request the numbers from a telecommunications operator (the CNMC allocates the ranges to operators, not directly to companies, and at Glofera we are an operator), configure your system so that sales calls go out identified with that number, and make sure your campaign complies with the rest of the telemarketing rules: consent, the Robinson List, and clear identification.

It sounds like paperwork, but it’s simpler than it looks if you follow the right order. Let’s go step by step.

What is 400 numbering and why do you need it?

400 numbering is the phone range reserved exclusively for commercial calls in Spain, as part of the Ministry for Digital Transformation’s anti-scam plan. Since October 2026, every sales call must be made from a number that starts with 400; those that aren’t can be blocked outright by operators.

The logic is simple: if every commercial call starts with 400, consumers know who’s calling before they pick up, and scammers who spoof numbers have a much harder time. For your company, the practical consequence is one: without 400 numbering, your sales team is left without a line.

If you want to understand in depth where the rule comes from, who it affects, and what happens if you don’t comply, we cover it in our guide to the 400 prefix for sales calls. Here we focus on the how: the process, the paperwork, and getting started.

Who assigns 400 numbering?

Short answer: the CNMC allocates numbering ranges to telecommunications operators, and your company contracts it with one of them. That means you don’t have to submit any application to the CNMC: the process is handled with an operator, just like when you sign up for a landline number or a new line.

And a clarification that hits close to home: at Glofera we are an operator, so we can assign your 400 numbering directly, with no intermediaries and no waiting on third parties. Numbering and PBX, from the same provider in a single process. In the months before each regulatory deadline there tends to be a backlog of applications; having the operator in-house is how you skip it.

Steps to process the 400 numbering registration

The full process, in order:

1. Audit your outbound calls. Separate which ones are commercial (sales, prospecting, promotions, renewals) and which are management or customer service. Only the former need the 400; mixing them up is the costliest mistake you can make.
2. Request 400 numbering from an operator. At Glofera, as an operator, we assign it to you directly: tell us how many numbers you need and for which campaigns: a team of three salespeople isn’t the same as a call center with twenty agents and several lines of business.
3. Demonstrate the commercial use of the numbering. The 400 is an end-use range: it can only be used for commercial calls. The operator will ask for your company’s details and the intended use before activating it.
4. Configure your PBX to select the outbound number depending on use. Sales → 400 number. Customer service or administration → your usual landline number. Ideally, each employee can choose it at the moment of calling, without touching any settings.
5. Run tests before launching. Check that calls from the 400 are delivered correctly and that the number displays properly on the recipient’s handset. A test call to your own mobile saves you headaches.

With that, the technical part is settled. Now comes the legal part of the campaign, which is where most companies stumble.

What documentation do you have to provide to the operator?

To register the 400 numbering, the operator (us, if you process it with Glofera) will ask for this documentation:

• A copy of the company registration certificate, or the entity’s tax ID (CIF/NIF; NIF if you’re self-employed).
• Registered or tax address in Spanish territory: street, number, postcode, and city.
• Identification of the account holder or legal representative making the application.

Nothing exotic: it’s the same information you handle in any routine company procedure. The trick is to send everything complete and correct the first time — every correction resets the registration clock.

How long does registration take once the documentation is submitted?

Short answer: with complete and correct documentation, registration of 400 numbering is usually resolved in a few business days, typically between two and ten depending on the operator. The range itself has already been allocated by the CNMC to operators, so the process is assigning you numbers from that range and activating them on your service, not opening an administrative file from scratch.

That said, the timeframe can stretch during demand peaks close to the regulatory deadlines, when half the country is requesting numbering at once. Translation: the sooner you process it, the shorter the road. And if you do it with us, numbering and PBX are activated in the same process: one point of contact and zero calls of the “that’s the other provider’s problem” kind.

What legal requirements must your telemarketing campaign meet?

Having 400 numbering allows you to call; it doesn’t give you permission to call just anyone. Before launching the campaign, go through this list:

• Legal basis for calling. Since the 2022 General Telecommunications Act, commercial calls require the user’s prior consent or a legitimate basis that supports them. Buying a database of dubious origin and starting to dial isn’t a strategy: it’s a fine waiting for a date.
• Check the Robinson List. Before every campaign, exclude anyone who has signed up to this registry to avoid receiving advertising. It’s mandatory and, besides, calling someone who has said they don’t want to be called is a waste of your team’s time.
• Identify yourself at the start of the call. Who’s calling, from which company, and for what purpose. Transparency isn’t just an obligation: with the 400 prefix in front, whoever picks up already knows you’re going to sell them something, so being upfront is your best card.
• Respect the customer’s wishes. If they ask not to receive any more calls, log it and honor it. Your database must reflect those objections in all future campaigns.
• Use each numbering for what it’s meant for. In our guide to numbering for sales calls we explain which number applies to each type of call. Customer service calls also have their own framework: the Customer Service Act, published in the BOE (the Spanish Official State Gazette) in December 2025, with maximum waiting times and the right to human attention. Each type of call, with its own number and its own rules.
• If your campaign includes SMS, register your alias. The CNMC requires alphanumeric senders to be registered in its official registry; messages with unregistered aliases are blocked.

What happens to the numbers you already have?

Short answer: you keep them all. 400 numbering doesn’t replace your current numbers, it adds to them. Your usual landline remains the face of customer service, the team’s mobiles keep working, and the 400 becomes the number for your sales campaigns.

The challenge is no longer having numbers: it’s managing them without it turning into chaos. Making sure every call goes out with the right number, that inbound calls reach whoever they should, and that nobody ends up with two handsets in their pocket. The way to achieve that is to centralize all your numbering in a virtual PBX: the landline, the 400, and any that come later coexist under one system, and each employee chooses which one to identify themselves with on every call.

An extra advantage: centralizing gives you visibility. You know which calls go out on each number, you can measure your campaigns, and you can show, if anyone asks, that you use each numbering for what it’s meant for.

How do you set up your campaign without slowing the team down?

This is where theory meets reality: your sales team calls from their mobile, from home, from the car. And the regulation doesn’t care where you call from, only what number you identify yourself with.

The solution is a virtual PBX that lets each employee choose the outbound number depending on the type of call:

• A sales call? You select your 400 numbering and you comply with the regulation.
• Following up with a customer or an incident? You go out with the customer service landline.
• Calling from a mobile or from a computer? It doesn’t matter: the number the customer sees is the one you decide, not the device’s.

For teams on the move (sales reps on the road, SMEs where the office is the owner’s mobile), this makes the difference between complying with the rule and going mad trying.

What if sales reps want to call from their mobile with 400 numbering?

They can, and with no odd tricks. What the regulation prohibits is using mobile numbering for commercial calls, not calling from a mobile device. They’re two different things: the number you identify yourself with and the device you dial from.

This is where Glofera’s PBX comes in: your sales rep calls from their mobile (on the road, between visits, from the car) and the customer sees the company’s 400 number, not the personal mobile. Before dialing, they pick the right identification with one tap: the 400 for a sales call, the company landline for following up with a customer. And if that day they’re working from the office, they can do exactly the same from the computer.

For the sales rep, nothing changes: they keep carrying the company in their pocket. For you, everything changes: every call complies with the regulation, gets logged, and goes out with your company’s image, not the personal number of whoever is making it. And since it isn’t software you install and hope for the best, we take care of getting it working with your team from day one.

Can we help you with registration and setup?

At Glofera we don’t sell you software and leave you alone with the manual: we analyze how your company calls today, assign you the 400 numbering as the operator we are, implement the PBX configured by use, and support your team through the change. For your people, calling stays as easy as ever; for you, every call goes out with the right number from day one.

Request your no-obligation consultation and launch your next telemarketing campaign with the regulation on your side, not against you.

Frequently asked questions about 400 numbering

Can I keep calling from my mobile with 400 numbering?

Yes. The rule regulates the number you identify yourself with, not the device you call from. With a virtual PBX, your team can call from a mobile or a computer showing the 400 numbering on sales calls.

What happens if I make commercial calls without the 400 prefix?

Operators can block them, so they simply won’t reach their destination. On top of that, you expose yourself to fines and to your customers associating your usual number with irregular practices.

Do I need different numbers for sales and customer service?

Yes. Commercial calls must go out with 400 numbering; customer service calls, with your usual numbering and in compliance with the Customer Service Act. They’re two different regulatory frameworks for two types of call.

How long does registration of 400 numbering take?

It depends on the operator and on demand at the time. Since at Glofera we are an operator and assign the numbering directly, registration doesn’t depend on third parties. Even so, applications pile up in the months close to regulatory deadlines: request it with weeks of margin, not days.

Last updated: 6 November 2026.

Sources: Anti-scam plan of the Ministry for Digital Transformation and the Civil Service (La Moncloa) · Customer Service Act (BOE) · CNMC SMS alias registry (El País) · The Government will impose the 400 prefix from October (El País) · Numbering for commercial calls 2026 (Cambios Legales)