The pitch is everywhere now. Put your own SIM in a phone, plug it into your CRM and text your whole customer list with no registration, no per-message fee and no compliance paperwork. One vendor says it powers more than 10,000 businesses that way. Most of them have never read the one document that decides whether their texts actually arrive. Here is what it says, in plain words, and what to do about it.
What a SIM gateway actually is
A SIM gateway is an app on an Android or iPhone. You keep your own SIM and your own carrier plan in the phone, install the app, and it pipes messages between that phone and your CRM. The texts leave from the phone's own number. GoHighLevel, HubSpot, Salesforce and Zoho are the usual integrations. The best known one, myCRMSIM, sells SMS at $970 a year, which works out to $80.83 a month, for up to 10 sub-accounts with one SIM per sub-account. iMessage and WhatsApp are $290 per line per year on top. We read those numbers off their pricing page twice on the same day, and both reads agreed.
People buy it for two reasons. It is cheaper than paying per message on a registered business route, and the headline promise is "No A2P Registration Required". Their own page goes further and says "no carrier blocks" and "no A2P compliance headaches", and one testimonial praises it as a way to avoid compliance bundles. That is the sale. The rest of this post is about the part the page leaves out.
The rule nobody reads: it is about who is sending, not what phone
US carriers work from a document called the CTIA Messaging Principles and Best Practices. The current version is dated May 2023. It sorts every text message into two categories, and the sorting has nothing to do with hardware. Section 3.3.1 defines a consumer as "an individual person who subscribes to specific wireless messaging services or messaging applications", and then says in the same breath that consumers "do not include agents, representatives, or any other individuals acting on behalf of Non-Consumers, including businesses, organizations, political campaigns, or entities that send messages to Consumers".
Section 3.3.2 closes the door from the other side. A non-consumer is "a business, organization, or entity that uses messaging to communicate with Consumers", and that includes "agents, representatives, or any other individuals acting on behalf of Non-Consumers". So when your office manager texts forty customers about a schedule change from a consumer SIM, the carrier does not see forty personal texts. It sees business traffic on a consumer road. The SIM does not change the category. It only means the traffic is unregistered, which is exactly the traffic the filters are built to catch.
"No registration required" is true in the narrow sense that nobody will hand you a form. It is not the same thing as "your texts count as personal". Those are two different claims, and the vendor's page only ever makes the first one.
What unregistered actually costs, and who pays it
The CTIA document says messaging providers deploy filters and may block traffic that looks like unregistered business messaging. Nobody sends you a fine. The messages quietly stop arriving, or the number stops sending. And the number in question is not the vendor's. It is your own line, the one on your business cards, your website and your invoices. That is the part worth sitting with for a minute. The gateway vendor risks nothing when the carrier acts. You risk the number your customers already know.
Be careful with how far we push this. We read the CTIA principles ourselves. We did not read every carrier's consumer plan terms, and that is where a "no commercial use" clause would sit if your carrier has one. So the honest advice is not "this will get you blocked". It is "read your own plan before you lean on it", which is the sentence you will not find on the gateway's sales page.
There is one tell on the vendor's own pricing page that says they know this. iMessage is capped at 50 unique contacts a day. SMS carries no cap at all and is sold as "Unlimited Messages". Per-channel throttles are real, and they put a number on the channel they control and left the risky one blank. Nowhere on the site does it say what happens if a carrier blocks your number. Not illegal. Just the part you find out later.
What registration actually is
The thing being skipped is called A2P 10DLC, which stands for application-to-person messaging over ten-digit long codes, meaning ordinary local phone numbers. To send business texts on one in the US, the business registers as a brand with The Campaign Registry, and a US brand registers with its EIN. The EIN has to match IRS records. Then the business describes the kind of messages it sends, which is the campaign. Carriers filter unregistered A2P traffic and let registered traffic through at normal speed.
- One EIN is one brand. An agency running several clients registers each client under that client's own EIN, not under the agency's.
- An EIN that does not match IRS records is the most common rejection, and a second verification carries a fee. Collect it, then check it, rather than storing whatever was typed.
- A business under about a year old may not be in the IRS database yet and needs its SS-4 confirmation letter to get through.
This is a carrier consortium rule, not a statute, which is why it feels optional. GoHighLevel has an EIN field for exactly this reason and leaves it soft, so people skip it and then wonder why their delivery rate fell off a cliff. We checked this against Twilio's own 10DLC documentation and HighLevel's brand approval help page rather than the registry's rulebook itself, so treat the mechanics as well sourced and the fine print as something to confirm with whoever provisions your number.
The two things a SIM does not change at all
Consent and content. The Telephone Consumer Protection Act, the TCPA, governs whether you were allowed to text that person in the first place, and it does not care which road the message took. A SIM does not buy consent. A registered route does not buy consent either. If you want the full picture of what consent looks like for outbound contact, we wrote it up in our guide to the legal side of AI cold calling, and the same principles apply to texting. The route is a carrier rules question. The consent is a statute question. Mixing them up is how most people get this wrong in both directions.
A SIM gateway changes the road your messages travel on. It does not change who you are, so it does not change what category your traffic is in, and it does nothing about whether you were allowed to send the message at all.
Two roads, and which traffic belongs on each
Here is the honest version, which neither the gateway vendors nor the registration vendors will give you, because each of them sells only one road. Some of your texting is conversation. A lead texts in, a person texts back. An appointment is confirmed. A quote question gets answered. That is one-to-one, it is slow, and it is the shape of texting a person does from a phone. Some of your texting is a campaign. Three hundred messages to a list at nine in the morning with the same wording. That looks exactly like what filters exist to catch, whatever SIM it leaves from, and it belongs on a registered route so it actually lands.
| Sending from your own SIM | Sending on a registered route |
|---|---|
| Right for one-to-one conversations, replies and confirmations | Right for campaigns, reminders at volume and anything to a list |
| You supply the handset, the SIM and the carrier plan | You supply your EIN and a description of what you send |
| Volume and speed are governed by your carrier and your plan | Volume and speed are governed by your registration tier |
| Nothing to register, nothing per message from the platform | Registration fees plus a per-message cost |
| What can go wrong: your carrier filters or blocks your own number | What can go wrong: a rejected registration delays sending until fixed |
This is how we built it at Multiply Revenue. You supply an Android handset with your own SIM and plan, we connect it once during onboarding, and your whole team texts from the platform with no per-message charge from us. How much you can send and how fast is governed by your carrier and your plan, not by us, and we say that on the pricing page rather than in the small print. Campaigns run on registered numbers, and we ask for your EIN before switching campaigns on, because US carriers require it before your texts will deliver. The follow-up sequences know which road each message belongs on, so nobody on your team has to.
Put plainly: the gateway-only vendors sell you one road and call the other one a headache. The registration-only vendors sell you the other road and charge you per message for the conversations that never needed it. Most businesses need both, and someone to send each message down the right one.
What to do this week
- Read your carrier plan for a commercial use clause
It takes ten minutes. If your consumer plan says business use is not permitted, you now know which number is at risk and can decide with your eyes open.
- Sort your texting into conversations and campaigns
Go through last month's messages. Replies, confirmations and answers are conversations. Anything you sent to more than a handful of people with the same wording is a campaign.
- Register a brand for the campaign half
Have your EIN as it appears on IRS records and, if the business is under a year old, the SS-4 letter. Do it once, per business, under that business's own EIN.
- Keep the consent record either way
Where the number came from, when they agreed and what they agreed to. No route removes this, and it is the one record that matters if anyone ever asks.
- Watch delivery, not just sends
A sent count tells you nothing. If replies on a number drop while sends stay flat, the carrier is already telling you something.
A note on the price argument
The gateway's own pricing page hands over one more fact worth knowing. People are paying $970 a year for texting alone, with the carrier risk sitting on their own number. Our Starter plan is $149 a month and includes the AI voice agent, the CRM, the follow-up sequences and texting on both roads. That is not the reason to choose one over the other. The reason is that one of them tells you which road your message is on, and the other tells you not to worry about it.
- CTIA Messaging Principles and Best Practices, May 2023, sections 3.3.1, 3.3.2 and 5.5.2, read directly.
- myCRMSIM.com homepage and pricing page, read twice on 21 September 2026 with both reads agreeing on every figure quoted.
- Twilio A2P 10DLC documentation and HighLevel's brand approval help article, for the registration mechanics.
- Our own pricing and texting terms as published on multiplyrevenue.com on the date of this post.
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