A Letter of Authorization (LOA) is a document that allows your VoIP provider to request and manage the transfer of your existing phone numbers from your current telecom carrier. Without it, your provider can’t access the information they need to complete the porting process, and your number transfer could be delayed or rejected.
If you’ve never heard of an LOA until you start switching providers, you're not alone. It's one of those behind-the-scenes telecom requirements that most businesses don't know about until it causes a delay. What seems like a simple signature can be the difference between a smooth onboarding experience and weeks of frustration.
At TeleCloud, we deal with LOAs every day. We understand where delays happen, what information gets missed, and how to get it right the first time. We also recognize that we have a vested interest in getting this part right quickly—because it affects your satisfaction with our onboarding.
In this guide, we’ll walk you through what an LOA is, why it matters, what to avoid, and how to make sure your transition to a new VoIP provider happens without disruption.
Table of Contents
- What Is a Telecom Letter of Authorization (LOA)?
- Why Is an LOA Required When Switching VoIP Providers?
- What Information Does a VoIP LOA Need to Include?
- What Do You Need to Provide for Your LOA?
- What Are the Most Common LOA Mistakes?
- What Happens If There’s a Mistake on the LOA?
- What Does a Smooth LOA Process Look Like?
- How Long Does the LOA Process Take?
- How Can You Speed Up the LOA and Porting Process?
- FAQs
What Is a Telecom Letter of Authorization (LOA)?
A Letter of Authorization (LOA) is a formal document specifically used for number porting in telecom. It gives your new VoIP provider permission to act on your behalf with your current carrier, allowing them to request the transfer of your phone numbers.
In simple terms, it enables your new provider to initiate and manage the porting process. Without it, your current carrier won’t authorize the transfer or release your numbers. It’s a required and regulated part of every porting request.
Why Is an LOA Required When Switching VoIP Providers?
The LOA is a critical safeguard. It prevents unauthorized number porting (also known as slamming) and ensures the request is legitimate.
Your VoIP provider needs this document to:
- Submit a port request to your existing telecom carrier
- Access essential details about your account
- Ensure the porting process is legally and technically valid
Put simply: without an LOA, nothing moves forward.
What Information Does a VoIP LOA Need to Include?
Your LOA must be accurate and complete to avoid delays. Here’s what it typically includes:
- Your business name (as it appears on your phone bill)
- Service address (not your billing address)
- Account number with your current provider
- Billing Telephone Number (BTN), especially with providers like Verizon
- List of all phone numbers to be ported
- Authorized user's name and role/title
- Port-out PIN, if required by your current VoIP provider
Your provider will often fill this out for you using the details from your most recent invoice, but you need to make sure the data you provide is current and correct.
What Do You Need to Provide for Your LOA?
To complete your LOA quickly and accurately, your provider will typically ask for:
- A recent invoice (within the last 2–3 months)
- A full list of all phone numbers you want to port
- Confirmation of the authorized user
It’s also helpful if you can request a Customer Service Record (CSR) from your current provider in advance. This record verifies all the numbers, any changes made, and account details on file.
What Are the Most Common LOA Mistakes?
Mistakes on the LOA are one of the top reasons a port request gets rejected. Common issues include:
- Mismatched business names or incorrect spelling
- Listing the billing address instead of the service address
- Using a former employee as the authorized user
- Missing or incorrect Billing Telephone Number (BTN)
- Incomplete list of phone numbers
Some carriers, like Optimum, are notorious for rejecting requests due to even small inconsistencies.
What Happens If There’s a Mistake on the LOA?
If there’s a mistake, the LOA itself won’t be rejected, but the port request will be. And that sets off a chain of delays:
- You’ll need to fix the issue and resubmit the LOA
- Your onboarding timeline gets pushed back
- It could delay your entire service migration
That’s why we recommend confirming the authorized user and reviewing your invoice early in the process.
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What Does a Smooth LOA Process Look Like?
Best case scenario? It looks like this:
- You send your most recent invoice
- Your provider pre-fills the LOA and sends it for e-signature
- Confirm all business names, addresses, and numbers are correctly listed and e-sign.
- The authorized user is confirmed
- You submit your porting request, and it gets approved without any rejections
- Installation and activation happen as scheduled
This is how an ideal process should unfold: clear, guided, and free of rejections or delays.
How Long Does the LOA Process Take?
The LOA is usually completed right after contract signing and is one of the first steps in onboarding.
Our typical onboarding timeline is 3 to 4 weeks from signing to activation. That includes:
- Gathering invoices
- Submitting the LOA
- Porting numbers
- Programming call flows
We plan for potential rejections so your business doesn’t face last-minute surprises.
How Can You Speed Up the LOA and Porting Process?
If you want to avoid delays, here’s how to make the LOA process smoother:
- Send your latest invoice as soon as possible
- Confirm who your authorized user is (and make sure they’re still with the company)
- Ask your current provider for a CSR
- Find out if there’s a Port-Out PIN required
- Provide all phone numbers, including lines for alarms, faxes, or unused numbers
The more prepared you are, the faster the transition.
Get It Right Before You Port
A Letter of Authorization (LOA) is a critical part of the number porting process in telecom. When done correctly, it enables a smooth transition from your current phone provider to a new one. When done incorrectly, it becomes the biggest cause of delays and frustration.
Businesses often underestimate how easy it is to get the details wrong. A misspelled business name or outdated authorized user can cause a port request to be rejected, stalling your onboarding by days or even weeks.
That’s why preparation matters. The right invoice, the correct list of numbers, and a verified authorized user can be the difference between a clean cutover and ongoing disruption.
If you're preparing to switch providers, make sure you get your LOA right from the start.
Schedule a call with a VoIP expert to avoid delays and get your numbers ported right the first time.
Frequently Asked Questions
What is the difference between a billing address and a service address?
The billing address is where invoices are sent, while the service address is the physical location where your phone services are used. The LOA must list the service address.
What if I don’t know who the authorized user is?
Check with your current provider or use a recent CSR (Customer Service Record). If the authorized user is outdated, you may need to update this before the port can proceed.
Can I port only some of my numbers?
Yes, but you must clearly list all numbers you wish to port on the LOA. Omitting any can lead to an incomplete transfer.
How long does it take for numbers to port after the LOA is submitted?
Once the LOA is submitted and accepted, porting typically completes within 1 to 3 weeks, depending on the carriers involved.
Do I need a Port-Out PIN?
Some VoIP or mobile carriers require a Port-Out PIN. Check your account settings or contact your provider to obtain it.
What happens if the LOA is rejected?
Your carrier will delay the port until the issue is corrected. Common reasons include mismatched names, wrong account numbers, or outdated authorized user information.
