osmo-remsim is a suite of software programs enabling physical/geographic separation of a cellular phone (or modem) on the one hand side and the SIM/USIM/ISIM card on the other side.

Using osmo-remsim, you can operate an entire fleet of modems/phones, as well as banks of SIM cards and dynamically establish or remove the connections between modems/phones and cards.

So in technical terms, it behaves like a proxy for the ISO 7816 smart card interface between the MS/UE and the UICC/SIM/USIM/ISIM.

While originally designed to be used in context of cellular networks, there is nothing cellular specific in the system. It can therefore also be used with other systems that use contact based smart cards according to ISO 7816. Currently only the T=0 protocol with standard (non-extended) APDUs is supported.

Both T=1 and extended APDU support can easily be added as a pure software update, should it be required at some future point.

Typical osmo-remsim deployment with 8 sim cards and two modems

Binary Packages

Osmocom provides binary packages for several flavors of Debian and Ubuntu GNU/Linux on a variety of architectures (i586, x86_64, armhf, armv7l). Unless you are a software developer interested in developing on Osmocom, it is recommended you use those packages instead of building from source.

For more details see Binary_Packages

User Manual

The latest user manual is available from

Presentation / Video

An early presentation video recording is available:osmo-remsim: Remote SIM card Software

Please keep in mind that this video was done at a relatively early point in the development, so not everything may still be correct today.

Source code

The source code is available from (module osmo-remsim).

Public read-only access is available via

git clone

You can also browse it via the web browser at

Contributions are welcome via Gerrit.

Test Suite

We have a TTCN-3 test suite as part of our Titan_TTCN3_Testsuites

Supported Hardware

SIM card readers/banks

  • lab / small deployments (less than 8 slots)
  • medium size deployments (8 slots or multiple)
  • large size deployments (96 slots and up)
    • sysmoSIMBANK-96 and sysmoSIMBANK-192 (19" units with 96 and 192 slots, respectively

Support for other SIM bank hardware or card readers can of course be added by either contributing related patches or funding related development.

Interface to Phone/Modem

  • sysmoQMOD (board with four mPCIe modem slots and remote SIM support)
  • simtrace2 (cannot only be used for tracing but also for card emulation by means of "cardem" firmware)
  • ngff-cardem (single-slot M.2/ngff modem carrier board with on-board microcontrolelr that can run the "cardem" firmware)

Contact / Getting Help

Contact us via

You can file issues (bugs / feature requests) using the redmine project you're currently viewing.

Authors / Credit

osmo-remsim was mainly developed by Harald Welte, with contributions from Kevin Redon.

Further pages in this wiki

Commercial Support

Commercial support as well as development, system integration and training services for this project are available from sysmocom

Updated by laforge 9 months ago ยท 16 revisions

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