2 layers85.6 × 54 mm
Magnetkarte
osmocom/osmocom-analog
Software Implementation of analog cellular telephony systems like NMT, TACS, IMTS, A/B/C-Netz; mirror of https://gitea.osmocom.org/cellular-infrastructure/osmocom-analog
10 parts32GPL-3.0
2 layers101.5 × 54 mm
Simkarte
osmocom/osmocom-analog32Software Implementation of analog cellular telephony systems like NMT, TACS, IMTS, A/B/C-Netz; mirror of https://gitea.osmocom.org/cellular-infrastructure/osmocom-analog
- Size
- 101.5 × 54 mm
- Copper layers
- 2
- Thickness
- 0.8 mm
- Parts
- 15
- Nets
- 12
- Pads
- 38
- Tracks, vias
- 95, 0
- Routed
- Yes
- KiCad
- KiCad 6 (file 20211014)
- Created
- 22 Jun 2019
- Updated
- 6 Dec 2025
Overview
Simkarte is an open-source printed circuit board by osmocom, from the osmocom/osmocom-analog repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 101.5 × 54 mm with 15 parts on 12 nets, routed with 95 tracks and 0 vias.
It is built around the ATTINY85-20PU. Its parts include 2 capacitors, 2 ICs and 1 connector. It belongs with the radio and wireless boards and the AVR (ATmega, ATtiny) boards of this library.
Main components
1README
READMEThis software implements base station protocol of classic mobile phones. With radio transmitter and receiver connected to one sound card and a headset connected to another sound card, it is possible to make and receive calls to and from mobile phone. With SDR (software defined radio) it can be use without radio equipment connected to a sound card, and even multiple channels can be generated simultaniously using SDR. Currently supported networks:
- A-Netz
- B-Netz (ATF-1)
- C-Netz
- NMT 450 / 900 (Nordic Mobile Telephone)
- AMPS (Advanced Mobile Phone System)
- TACS (Total Access Communication System)
- JTACS (Japanese version of TACS)
- Radiocom 2000 (French network)
- IMTS / MTS ((Improved) Mobile Telephone Service)
- MPT1327 (Trunked Radio) aka known as 'Buendelfunk'
- Eurosignal (ERuRD paging service)
- 5-Ton-Folge (ZVEI 5 tone paging code for pager and siren trigger)
- JollyCom (Unofficial network, invented by the author)
- C-Netz BSC (Connecting to a C-Netz Base Station)
Additionally the following communication services are implemented:
- TV Transmitter with test Images
- Radio transmitter / receiver
- Analog Modem Emulation 'Datenklo' (AM7911)
- German classic 'Zeitansage' (talking clock)
- POCSAG transmitter / receiver
- Golay/GSC transmitter / receiver
- DCF77 time signal transmitter and receiver with weather info
- C-Netz SIM emulator
- C-Netz magnetic card emulator
USE AT YOUR OWN RISK!
Acknowledgements:
Carsten Wollesen for donating Telefunken 4015 B-Netz phone back in the 90's.
Klaus Adler for helping me to retrieve complete NMT specification and donating a BSA44 (magnetic card C-Netz hackable phone) back in the 90's.
Andy Zauner for providing signaling specification of C-Netz back in the 90's.
Hans Wigger for providing valuable information about A-Netz and B-Netz and helping me to get an A-Netz phone.
Stephan Hessberger for his work on oebl.de, that provides valuable information about A-Netz, B-Netz, C-Netz, Eurosignal and much more.
Friedhelm Hillebrand for providing complete specification of the mobile phone of C-Netz.
Mikko Ristila for providing newer NMT specs (with DMS/SMS specifications).
Dieter Spaar and Mark Atherton for providing AMPS information and recordings to verify and debug AMPS support. See http://www.idesignz.org/AMPS/AMPS_BS.html for first base station implementation of AMPS.
Telecommunication Industry Association for providing TIA/EIA-533 documentation. "Reproduced under written permission from Telecommunications Industry Association."
Eric from Smart Card World and Karsten Niehusen from cardomatic.de for providing memory cards to be programmed for older C-Netz phone.
Dieter Spaar providing TACS recordings to verify and debug TACS support.
Hans Wigger providing Radiocom 2000 recordings, to reverse-enigineer the standard, which seems not to exist anymore...
Peter, Peter, Friedhelm and Stephan for providing documentation and hardware for C-Netz Base Station and other C-Netz documents.
Carsten Wollesen for donating MPT1327 radios and programming tools.
Parts
15| Qty | Value | Footprint | References |
|---|---|---|---|
| 2 | C | Capacitor_SMD:C_0603_1608Metric | C1, C2 |
| 1 | ATtiny85-20PU | Package_DIP:DIP-8_W7.62mm_Socket | U2 |
| 1 | ATtiny85-20PU | simkarte:SO-8_falschrum | U1 |
| 1 | CLOCK | simkarte:tp_for_sim | TP6 |
| 1 | GND | simkarte:tp_for_sim | TP2 |
| 1 | Jumper_3_Bridged12 | Jumper:SolderJumper-3_P1.3mm_Bridged12_RoundedPad1.0x1.5mm_NumberLabels | JP1 |
| 1 | LOGO | simkarte:ctel | G*** |
| 1 | LOGO | simkarte:stollberg | G*** |
| 1 | MISO | simkarte:tp_for_sim | TP4 |
| 1 | MOSI | simkarte:tp_for_sim | TP3 |
| 1 | RESET | simkarte:tp_for_sim | TP7 |
| 1 | SCK | simkarte:tp_for_sim | TP5 |
| 1 | SIM_Card | simkarte:SIM-Pads | J1 |
| 1 | VCC | simkarte:tp_for_sim | TP1 |
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Questions
How big is the Simkarte PCB?
It measures 101.5 × 54 mm and has 2 copper layers, 0.8 mm thick.
What parts does the Simkarte use?
15 parts, built around the ATTINY85-20PU. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Simkarte KiCad files?
From the osmocom/osmocom-analog repository on GitHub, at the commit this page was made from: the board is layout/kicad/simkarte.kicad_pcb and its schematic layout/kicad/magnetkarte.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Simkarte design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).