'eSim' Previewed 2 Weeks Early... One Phone, Two Numbers Starting September 1

Easy Self-Activation via QR Code Scan... Separation of Personal and Business Lines

[Asia Economy Reporter Oh Soo-yeon] Starting September 1, eSIM (embedded SIM) will be officially introduced, allowing users to use two phone numbers on a single smartphone. As the three major telecom companies have built the related systems and completed preparations for service launch, we took an early look at activation, calling, and data usage methods with LG Uplus ahead of the full-scale introduction of the eSIM service.

Activation Complete by Simply Scanning a QR Code

On the 17th, LG Uplus held a "Smartphone eSIM Study" event in Jongno-gu, Seoul, explaining related technologies and preparation status ahead of the eSIM introduction. eSIM performs the same role as a USIM but, unlike the physical USIM card, it is embedded inside the device. When activating the device, users download the carrier profile to the eSIM by using a QR code or similar method. The download fee is 2,750 KRW, which is only one-third the cost of a USIM.

The biggest feature of eSIM is that when used together with a traditional USIM card, one device can have two numbers or use different mobile carriers. This makes it possible to separate numbers for personal, work, or overseas use, or to use voice calls via SK Telecom and data services via LG Uplus, for example.

Apple started equipping iPhones with eSIM from the iPhone XS model released in 2018, and Samsung Electronics introduced eSIM starting with the Galaxy Z Fold and Flip4 models released on the 10th.

Seok Taeyoung, head of the Mobile Device Development Team at LG Uplus, is demonstrating eSIM activation.

LG Uplus demonstrated the procedure for activating eSIM on an iPhone. After scanning the QR code with the smartphone and downloading the carrier profile, activation proceeds. A "Add Cellular Plan" page appears where users can select labels for each cellular plan. For example, users can input labels such as Personal, Secondary, Main, Work, or Travel to distinguish lines. Then, the primary line used mainly for calls and messaging is selected.

Next, the line to be used for iMessage and FaceTime is chosen. Since iPhone allows only one messenger app installed, users must decide which number to use for messaging services. Samsung Galaxy supports a "Dual Messenger" feature, allowing two messenger apps like KakaoTalk to be installed and used simultaneously on one device. Finally, the line mainly used for data is selected, completing the eSIM activation process.

What happens when calls come in on both the USIM and eSIM numbers? LG Uplus also demonstrated scenarios for calls and data usage while using dual SIMs. eSIM devices operate in DSDS (Dual SIM Dual Standby) mode, where two SIM cards are either on standby simultaneously or used in time-sharing mode.

Seok Tae-young, head of LG Uplus Mobile Device Development Team, who led the demonstration, explained, "While on standby or using internet data, the non-data-using line is periodically monitored for incoming calls, but during a call, only one line is exclusively used."

Seok Taeyoung, head of the Mobile Device Development Team at LG Uplus, is demonstrating the use of eSIM. Icons indicating the main and secondary line carriers and signal strength are visible at the top of the smartphone.

While on standby, icons showing the main and secondary line carriers and signal strength appeared at the top of the smartphone. However, when a call came in on either the main or secondary line, the other line's status changed to "No Service."

Create Your Own Mobile Carrier Combination to Save on Fees

Previously, the three major carriers offered additional services providing two numbers, but these were limited to use within the same carrier and required entering codes like '*77#' before making calls, which was inconvenient. With eSIM, users can combine plans from different carriers, and the usage method for the main and secondary lines is the same.

Some speculated that dedicated plans would be launched alongside eSIM to reduce communication costs, such as combining the three major carriers' voice and text plans with cheaper MVNO data plans. However, an LG Uplus official stated, "We are not considering separate dedicated plans," adding, "With eSIM, all current 5G and LTE plans offered by carriers can be used."

Bundled discounts and selective contract discounts are supported the same as with USIM. Only one line can receive the official subsidy. The issue of having two device identification numbers (IMEI) has been resolved by registering and managing two IMEIs. IMEI is a unique number assigned by manufacturers worldwide to identify devices, similar to a smartphone's resident registration number. During last year's eSIM introduction discussions, concerns were raised that having two IMEIs with dual SIMs could cause problems in lost device systems.

According to the Global System for Mobile Communications Association (GSMA), eSIM is currently used in 69 countries including the United States and Japan. It is expected that over 500 million smartphones worldwide will have eSIM this year, increasing to more than 2.4 billion by 2025.