BTS 850-02 Standard bus telephone

Official Siedle Documentation

• http://www.siedle.de/App/WebObjects/XSeMIPS.woa/cms/page/locale.enDE/pid.221.226.1963/agid.3655.3659.2402/ecm.ag/BTS-850-02.html

The PRI 602-… USB and ZBVG 650-… are required for programming. Interfacing relay accessory ZAR 850-… retrofittable, e.g. for actuation of an additional signalling unit.

It is currently not known whether this product uses software licensed under the GNU General Public License.

Hardware

• The PCB labeled "BTS850-0 X34289" (from 2008) contains NXP P87C54X2BBD MCU (8051 derivative 80C51 8-bit microcontroller family) with BTS 850 firmware (16 kilobytes of one-time programmable memory - so no firmware updates) from around 2003
• The PCB labeled "BTS850-02 X36902" (from 2015) seems to contain a similar NXP MCU but seems to be a simpler overall construction with less components. It has ha Nu701 Siedle-branded chip (for replacing much of the earlier discrete circuitry?) that is apparently connected to the In-Home-Bus Ta and Tb
• Connection to "bus cores Ta and Tb" - not to Sa and Sb

Software

• TBD

Protocols

• Siedle In-Home-Bus seems to be proprietary and undocumented. Needs independent security research. (Note to the manufacturer, "security by obscurity" never works. Please document the Siedle In-Home-Bus.)
• Compatible partial implementations seem to be available, e.g., from https://www.nello.io/

Developers

• TBD