#sysmoISIM-SJA5

sysmoUSIM-SJS1 Explained | HKCARD’s Programmable MVNO SIM Card Manufacturing

Discover the sysmoUSIM-SJS1, a programmable Java-capable SIM/USIM card for GSM/UMTS networks, and how HKCARD Electronics Co., Limited, a leading MVNO SIM card manufacturer, offers similar customizable MVNO Java SIM cards, LTE 4G USIM cards, and blank SIM cards for telecom operators. Contact us for scalable SIM card solutions.

 

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What is the sysmoUSIM-SJS1?

The sysmoUSIM-SJS1 is a standards-compliant, programmable SIM/USIM card developed by sysmocom, designed for authentication in GSM (2G) and UMTS (3G) cellular networks. It combines GSM SIM and UMTS USIM functionalities into a single, Java-enabled card, allowing operators and developers to reprogram credentials like IMSI, ICCID, Ki/OP/OPC keys, and the entire filesystem (EF/DF directories). Intended for public or private mobile network operators and the research community, it supports reprogramming via tools like pySim and sysmo-usim-tool, making it ideal for testing, prototyping, and custom network deployments, or we will provide software to program the sim cards.

 

As a leading MVNO SIM card manufacturer with over 15 years in the mobile phone SIM cards industry, HKCARD Electronics Co., Limited offers comparable programmable SIM solutions, including MVNO Java SIM cards, MVNO LTE 4G USIM cards, and replacement blank SIM cards. While the sysmoUSIM-SJS1 (discontinued as of October 2020) targets open-source ecosystems like Osmocom and sysmoBSC, HKCARD’s products provide scalable alternatives for commercial MVNOs and MNOs, extending support to LTE/4G and beyond.

 
 

Key Features of the sysmoUSIM-SJS1The sysmoUSIM-SJS1 is engineered for flexibility and compliance, with a focus on developer-friendly configuration:

  • Multi-Form Factor: Available as combined 2FF+3FF (mini + micro SIM) or 2FF+4FF (mini + nano SIM) cards, ensuring compatibility with various devices.
     
     
  • Programmable Credentials: Full reprogramming of IMSI, MSISDN, ICCID, Ki/K/OP or OPC (OPC default), and filesystem structures for custom profiles.
     
  • Authentication Algorithms:
    • GSM: COMP128v1 (default), COMP128v2/v3, XOR, MILENAGE.
    • UMTS: MILENAGE (default), XOR.
       
       
  • Java Capabilities: 64 kB flash storage for Java applets, including Card Manager, OTA (Over-the-Air) updates, and SIM Toolkit (STK/SAT) for value-added services.
     
     
  • Security Features: Card-individual ADM (Administrative) key and OTA keys (3DES) for secure reprogramming; hacker/developer-friendly defaults (writable fields, reduced applet security for quick development).
     
     
  • Standards Compliance: GSM TS 11.11 for backward compatibility; supports use in UMTS (3G) and LTE core networks, though primarily focused on 2G/3G.
     
     

Pre-provisioned with test profiles, these cards ship in packs (e.g., MOQ of 10) and are programmed using a PC/SC-compatible reader.

 
 

How the sysmoUSIM-SJS1 WorksThe sysmoUSIM-SJS1 operates as a secure, multi-mode identity module:

  1. Provisioning and Programming: Connect to a PC/SC reader and use pySim (e.g., pySim-prog.py) or sysmo-usim-tool for updates. Authenticate with the card-individual ADM key to modify IMSI, keys, and filesystems. For example, sysmo-usim-tool.sjs1.py allows setting SIM mode (classic SIM or USIM), algorithms, and ICCID.
     
     
  2. Authentication: Performs challenge-response using selected algorithms (e.g., MILENAGE for mutual auth in UMTS); supports both GSM SIM and USIM modes.
  3. Java and OTA Functionality: Java applets enable dynamic services like STK menus or remote updates via OTA, secured by 3DES keys.
  4. Network Integration: Compatible with Osmocom stacks (e.g., sysmoBSC), OpenAirInterface (OAI), or any GSM/UMTS/LTE core, allowing seamless subscriber authentication.

This makes it suitable for rapid prototyping in research or private networks, though it’s not intended for end-user cloning due to fixed ICCID and security measures.

 
 

Applications of the sysmoUSIM-SJS1The sysmoUSIM-SJS1 is tailored for specialized telecom scenarios:

  • Private Mobile Networks: Custom profiles for sysmoBSC-based GSM setups or Osmocom environments.
     
    tegakari.net
  • Research and Development: Programmable features for protocol testing, network simulation, and OAI integration.
     
     
  • UMTS/3G Deployments: Reprogrammable USIM for legacy 3G networks or hybrid GSM/UMTS cores.
  • Developer Testing: Java-enabled for STK/SAT apps, OTA prototyping, and algorithm experimentation.

 

 
 

HKCARD’s Comparable Programmable SIM SolutionsWhile the sysmoUSIM-SJS1 provides valuable programmability for 2G/3G niches, HKCARD Electronics Co., Limited offers production-scale alternatives optimized for modern MVNOs and MNOs:

  • Programmable SIM Cards: Our MVNO Java SIM cards (e.g., 1/2 SIM JAVA 128K) mirror the SJS1’s Java capabilities and OTA support, with 64 kB+ flash for applets like STK/SAT.
     
    tegakari.net
  • Multi-Standard Support: MVNO LTE 4G USIM cards extend beyond SJS1’s GSM/UMTS to include LTE/4G, MILENAGE/XOR algorithms, and IMS/VoLTE, with customizable IMSI/Ki via SIM card personalization.
  • Form Factors and Compatibility: Full SIM cards, half SIM, quarter SIM, 2FF SIM cards, and embedded options; supports CDMA SIM cards and RUIM cards for CDMA2000 1X/EVDO.
  • Security and Tools: ADM-like secure keys for reprogramming; rigorous SIM card testing and USIM test solutions ensure compliance, similar to SJS1’s developer-friendly defaults.
  • Scalability: Bulk SIM card supply for global operators, including as an MVNO SIM card manufacturer in Africa, with DDP shipping to 80+ countries—far surpassing SJS1’s research focus.

HKCARD’s replacement & blank SIM cards enable telecom personalization akin to SJS1’s filesystem edits, ideal for prepaid/postpaid SIM cards and IoT. Clients value our versatility: “HKCARD’s programmable SIMs offer SJS1-level customization with enterprise scalability.”

 
 

Why Choose HKCARD for SJS1-Like Programmable SIMs?HKCARD excels where sysmoUSIM-SJS1 falls short in availability and scale:

  • Extended Compatibility: Beyond GSM/UMTS to WCDMA SIM cards, 3G SIM chips, and modern MVNO networks.
  • Global Expertise: SIM card supplier in Africa and worldwide, addressing “SIM card manufacturer in Africa” with efficient logistics.
  • Innovation: Programmable SIM cards for Java telecom, native SIM, and future-proof 5G transitions.

Contact HKCARD Electronics Co., Limited: Your SIM Manufacturing PartnerReady for programmable SIM solutions inspired by sysmoUSIM-SJS1? HKCARD delivers MVNO Java SIM cards, LTE 4G USIM cards, and blank SIM cards tailored for your needs. Contact us at  or +8615817372512 for a free consultation. Visit our website to explore SIM card manufacturing and telecom solutions, and join our global network of partners.

 

  1. sysmoUSIM-SJS1: Programmable SIM/USIM Card Explained with HKCARD Alternatives
  2. HKCARD’s MVNO Java SIM Cards: Matching sysmoUSIM-SJS1 for GSM/UMTS Networks
  3. Reprogrammable Credentials in sysmoUSIM-SJS1: HKCARD’s Custom USIM Solutions
  4. sysmoUSIM-SJS1 Tools and Features: HKCARD’s Bulk SIM Card Supply Options
  5. Java-Enabled SIM Like sysmoUSIM-SJS1: HKCARD’s Global Telecom Expertise

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Best Regards
Byron


HKCARD ELECTRONICS CO.,LIMITED
Whatsapp/wechat:+8615817372512
Skype/Teams：byron1681
Email：byronhan@cardmfg.com