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Luke Deitz , Jun 13, 2019

It was a summer in the late 2000’s when my sliding keyboard phone became unusable. I wasn’t about to ask my parents for a new phone, so I took the SIM card out of it and went into the garage on a mission. I pulled out a dusty plastic bin that held an assortment of discarded cords, spare batteries, chargers, and emptied phones. At the bottom, I found a small silver flip phone and placed it aside. I pulled the SIM card out, hopeful that my plan would work. I carefully placed it into the silver flip phone and within minutes, it was all restored – we’re talking all contacts, text messages, settings, everything. It was ready to be used.

Even as a kid, I knew the SIM card was important…it was, after all, the only thing that made my DIY repair possible. But as the era of the flip phone ended and smartphones took over, things changed…and for the consumer, these changes weren’t always better.

I’ll speak more about this below, but first I’d like to cover the history and highlights of the SIM card. I’ll also be considering the question: with a new decade right around the corner, what does the future hold for the SIM card?

What is a SIM Card?

In layman’s terms, a SIM (Subscriber Identity Module) card is a tiny, portable memory chip that stores information about you as a cell phone user. On it, there’s a seventeen-digit code that designates its country code of origin, the system carrier (such as AT&T or Verizon), and a unique user ID.

You may wonder, “Who cares about this code?” A valid question and guess what: phone carriers do. It’s how they attribute cell phone bills and charge us.

Above all else, SIM cards are super handy because they can be easily transferred from one device to another. Just like in my opening story, all that you’d need to do is take it out of one phone and slip it into the new one. By making the switch, most (if not all) of your contacts and personal settings will transfer with it, making life all the easier.

History of SIM Cards

SIM cards were introduced all the way back in 1991. The first SIM card was about the size of a credit card. Since then, there have been several updates and iterations, making them smaller and smaller.

This evolution closely aligns with the history of the GSM (Global System of Mobile Communications) mobile network. Developed to describe protocols for second generation (2G) cellular networks, the GSM today stands as the default global standard for mobile communications.

SIM cards are a crucial part of GSM networks, storing user information required for authentication. Ultimately, this allows both your phone to connect with a GSM network and GSM networks to track your phone usage (specifically, your minutes, texts, data usage, etc), giving carriers the information to send you an accurate phone bill.

GSM is the standard network in Europe, Asia, Africa, and most other places. Interestingly, besides GSM, the United States has an additional network called CDMA (Code Division Multiple Access) that is used by carriers such as Verizon and Sprint. Phones on the GSM or CDMA network can use any carrier’s network, lowering the costs for the carriers and its users.

When it comes to your phone’s connection with either network, SIM cards are essentially the brain of your device.

Different Types of SIM Cards

There are three basic sizes of SIM card: the standard, the micro, and the nano.

Of the three, the Standard is the original SIM and the largest. Today, these are mainly used on older phones.

The Micro SIM card is essentially a standard SIM card with the extra plastic around the circuit board trimmed off.

A trimmed version of the Micro, the Nano is the smallest and used on today’s iPhones. Although minuscule compared to prior versions, the Nano still holds the same amount of data as earlier SIM cards.

Mini-SIM

When skimming the evolution of the SIM card, you likely noticed that they’ve become much smaller. But prior to the launch of the iPhone 4 in 2010, we really only had one SIM card size. Introduced in ‘96, it was the standard used in every phone and it made the GSM folks happy. Essentially, it was your entire phone on a card. It made things simple. If you wanted a new phone, all you’d need to do was take that SIM out, pop it into any phone and suddenly your phone number would be transferred to the new device. For over a decade, this was the standard, which made switching phones a breeze. Now? Not so much.

Micro-SIM

Enter Apple. Wanting to save precious room for its newest generation of smartphones, Apple switched from using the standard Mini-SIM to the Micro-SIM once the iPhone 4 hit shelves.

Surprisingly, the Micro-SIM wasn’t some new flashy SIM developed for the latest iPhone. Believe it or not, it was first introduced in 2003.

Back then, its purpose was clear: if a device was too small to fit a mini-SIM, you’d have to use the micro-SIM. In addition, the micro-SIM was designed for backward compatibility, meaning it can work with input generated by an older version of the SIM (such as the Mini-SIM).

In addition, despite its smaller size, the micro’s performance wasn’t impacted at all, as chip’s contact area remained the same. It turned out to be scaled down – the card only needed its excess plastic to be cut from it.

When Apple released the iPhone 4 with the micro-SIM, it became the standard for most smartphones. Samsung, Nokia, and HTC are just a few of the manufacturers that adopted the new Micro-SIM. During this time, several upgrading to the iPhone 4 opted to use an adapter to get their SIM cards cut down to Micro’s, as well. Check out a video of this in action:

Nano-SIM

If you thought Apple was done using smaller SIM cards, think again. Perhaps Apple was peeved they had to use a SIM card from 2003 on the shiny new iPhone 4. Maybe they just wanted to stay ahead of the curve and throw competitors off their trail.

In any case, the launch of the iPhone 5 prompted the public to realize there was a new SIM in town: the Nano-SIM. This choice to go small made life pretty difficult for users. Anyone upgrading to an iPhone 5 or switching from Android now had to get a new SIM card or an adapter.

Fortunately, most smartphones released since 2014 (both iOS and Android) now support Nano SIM card technology as the standard. Still, it’s sad to see a card that small take over, as it was always much easier changing phones with the Standard SIM compared to the Nano.

eSIM and Soft SIM

Now, where will the SIM card go in the future? Judging from the trend, it’ll likely be the size of a speck of dust, so insignificant that you wouldn’t even feel it in your hand.

No. I’m joking, that would be horrible. But get this: the next version of the SIM likely will be impossible to hold. That’s because it will be entirely virtual.

Cards like the eSIM and the Soft SIM are looking to be the next carnation of the SIM card we’ll see, a software “card” that carries all of the SIM’s original functions without any of the plastic or brass hardware bits.

One cool aspect of this new class of SIMs is that subscribers are able to switch operators easily, without swapping the physical SIM card. Given that this transfer is possible, maybe software-based cards are the answer when it comes to the hassles that came with switching phones over the years.

But despite its conveniences, the eSIM and soft SIM have its detractors – especially around the issue of security. One potential risk that has been raised by networks regarding these SIMs is the issue of security. With hackings only becoming more prevalent, perhaps it’s hasty to lock all of a subscriber’s credentials and data into the OS of their device without building better cyber defenses against them.

It’s plausible that as the eSIM and Soft SIM are further developed, risks will be addressed until this version of the SIM overshadows the physical SIM, rendering it obsolete. In a way, it’s surprising that the SIM is only at this point of going digital now. As a product of the 1990’s, it’s amazing to consider the SIM card’s evolution, especially when compared to how fast other technologies of the era morphed and died out as newer solutions were innovated. As a link tying together the subscriber’s phone data with their network, the SIM card’s purpose has always been clear – but it will be interesting to watch what another two decades do for the future of this purpose and the SIM card itself.

Category: Cell Phones
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