User's Manual

Editor : KK Ko Document name Project code

ECO / DF No.

Version: 0.1 Jun. 07. 2007

File: User Manual for BH_HM_Fob

Identification No. : Document No.

Page 4 / 6

Comunicado como segredo empresarial. Reservados todos os direitos.

Confidado como secreto industrial. Nos reservamos todos los derechos.

Weitergabe sowie Vervielfältigung dieser Unterlage, Ver

wertung und Mitteilung ihres Inhalts nicht gestattet, soweit

nicht ausdrücklich zugestanden. Zuwiderhandlungen ver

sondere für den Fall der Patenterteilung oder GM-Eintragung

Technical aspects of 125 kHz – magnetic field:

• virtually no reflections,

• cubical decrease of field strength → allows good range control,

• released frequency band (ISM),

• high penetration,

• low quiescent current demand due to 125 kHz input stage (SMART KEY FOB),

• less sensitive for detuning compared to higher frequency.

For the down-link from the SMART KEY FOB to the vehicle, the standard radio frequency

(RF) is used (similar to the classic remote control functions) with FSK modulation.

1.3 System Overview / Block Diagram

Figure 1: Principle of Communication

ECU sends LF challenge via exterior antenna

ID tag sends identification code to RF receiver

Doors are unlocked automatically

User pulls open the door