What is Dummy SIM Card

If your first association with the term “dummy SIM card” was “a dumb SIM card,” you’re on the right track. That’s not the full story, since the term can refer to a somewhat dumb SIM card with several minuscule modifications you wouldn’t even notice. Regardless of which type it is, they share a purpose—to act as a SIM card replacement. We’ll explore its forms and use cases, but that hopefully piqued your interest. It’s also important to know you might struggle to acquire one. That’s for reasons that will become apparent shortly. Now, let’s answer, “what is a dummy SIM card?”

Dummy SIM card: What is it?

A dummy SIM card represents an imitation of a regular SIM card, except it is not tied to any particular carrier. In fact, in the vast majority of cases, it has no connection to anyone excluding the manufacturer. The card goes through the same production process we outlined when we described how SIM cards are made. As mentioned, it undergoes a few minor alterations and is produced in drastically fewer batches than a regular SIM. Let’s define a dummy SIM card through its features:

Electronics

Dummy SIM cards use identical electronics as regular SIM cards, i.e., a MOS IC (integrated circuit) chip. This allows it to store a limited amount of data in its flash memory, usually EEPROM (electrically erasable programmable read-only memory). Depending on the cost, production numbers, and goal, dummy SIM card electronics may be modified to reduce the memory compared to commercial SIM cards. Moreover, it lacks the components necessary to connect to a network, unless it’s created with that in mind.

Size

Because they must still fit into devices with a SIM card slot for testing, dummy SIM cards use standard SIM card sizes. This is in no way a rule, however. Manufacturers undoubtedly create all kinds of sizes in preliminary phases, with or without the plastic rim, to test specific features or functionalities. However, the ones sold by third-party sellers for purposes #3, #4, and #5 below tend to be of the aforementioned size.

Storage

As mentioned above, the storage capacity depends on the design of the dummy SIM card. If intended for testing of commercial perks, it’ll likely have EEPROM memory with between 8 KB and 256 KB of data. If not, to save costs, it may have a low-cost erasable programmable memory only sufficient for pivotal testing.

Dummy SIM card vs. blank SIM card

If you read our article on SIM card readers and cloning a SIM card, you’re rightfully confused. Doesn’t a blank SIM card look eerily similar to a dummy SIM? It sure does! Thus, before we proceed, it’s important to clarify some distinctions between dummy SIM cards and blank SIM cards:

Where is dummy SIM card used?

Dummy SIM card has several distinct practical applications:

SIM card manufacturing

One of two primary uses of dummy SIM cards is to experiment in manufacturing regular SIM cards. When a factory has a prototype in mind or wants to test new features and functionality, they use a limited number of dummy SIM cards. This is cost-effective, and they don’t incur massive financial losses if the experiment ends a failure. Additionally, they don’t risk reputation and business contacts with carriers, or shipping thousands of faulty SIM cards to end-users they must reclaim afterward.

Quality control

The second main use of dummy SIM cards is in quality control. Obtaining new equipment, personnel, or trying a new manufacturing process on thousands of commercial SIM cards would be ludicrous. Therefore, manufacturers employ dummy SIM cards to conduct testing. This also applies to mobile phones—dummy SIM cards are integral to quality control after assembling mobile phone components. It wouldn’t be time-efficient, cheap, or smart to activate a regular SIM card on every phone separately.

Privacy-oriented users

Mobile phones allow us to stay in touch wherever we go. However, that means your carrier, and by proxy, other people can locate you through nearby network towers. Suffice it to say, some people aren’t happy. Yet, their smart devices annoy them with notifications or forbid them from accessing certain features or applications or even getting to the home screen. Inserting a dummy SIM card eradicates all notifications, lets them install apps (particularly chatting ones), and use certain features thanks to the data on a dummy SIM. Meanwhile, users don’t connect to any particular network or have to recharge balance or pay monthly bills only so their devices work.

Porting numbers

Switching carriers while keeping your phone number involves bureaucracy, which requires time to complete. Although we (and carriers) suggest you should use the old SIM until it gets deactivated, that isn’t possible in all countries. For instance, in some countries in Europe, it’s common for a carrier to send you a dummy SIM card you can use to access their network until the actual SIM card gets activated. The dummy will only work for the scheduled period, e.g., 7 days, and automatically stop working afterward.

Old phones

While the support for feature phones produced in recent years isn’t going away, carriers are shutting down their 2G network and moving on from “dumb” phones. While they, too, should in theory work without a SIM card, many lock up and only permit emergency calls. Others refuse to boot memory and shut down shortly after you try booting them. In those cases, inserting a dummy SIM card bypasses the “Emergency Mode” and allows access to the home screen.