Omron Automotive Electronics Korea OKA-240T RF Keyless Entry System (Transmitter) User Manual
Omron Automotive Electronics Korea Co., Ltd. RF Keyless Entry System (Transmitter) Users Manual
Users Manual
OMRON
AUTOMOTIVE
ELECTRONICS
KOREA
OKA-240T
Transmitter, RF Keyless Entry System
Table of contents
1. Constitution of the Radio Frequency Keyless Entry system Controller
for vehicle ................................................................................................................. 1
2. User's manual (provisionally) ............................................................................... 2
3. Block diagram ........................................................................................................... 3
4. Specification ............................................................................................................... 4
5. Features ...................................................................................................................... 5
This device complies with part 15 of the FCC Rules. Operation
is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) This device must accept any interference received,
including interference that may cause undesired operation.
Caution:
Any changes or modifications to the equipment not expressly approved
by the party responsible for compliance could void user's authority
to operate the equipment.
1. Constitution of the Radio Frequency Keyless Entry
System for vehicle
The radio frequency keyless entry is a system that it controls locking and unlocking the door and
the
trunk by wireless remote controller. This system consists of three components. The TRANSMITTER is a device
that transmits the signal when the button is pressed. The transmission signal consists of several synchronous
codes , unique identification code , security code and function code. The RECEIVER is fixed inside the
vehicle. It works intermittently to prevent the battery exhaustion. When the receiver detects
the
synchronous code, it runs continuously to receive the signals completely. After receiving the signal, the receiver
decides which operation will be performed. The user can select the following operations by pressing the
button of the remote transmitter.
OPERATION ACTION
LOCK lock the door
UNLOCK unlock the door
PANIC alarm the horn
Transmitter
f = 307.9MHz
- 1 -
2. User's manual (provisionally)
REMOTE TRANSMITTER
You can lock and unlock your vehicle with the remote transmitter.
LOCK
When you push the LOCK button, all the doors will lock.
You cannot lock any of the doors with the remote transmitter if any door is open or the key is
the
ignition switch.
UNLOCK
When you push the UNLOCK button, all the doors will unlock.
You cannot unlock any of the doors with the remote transmitter if any door is open or the key is in the
ignition switch.
PANIC
When you push the PANIC button, horn will alarm.
- 2 -
UNLOCK
LOCK
PANIC
UNLOCK
LOCK
PANIC
3. Block diagram
This is block diagram concerning to the transmitter
LOCK
UNLCOK 8BIT
CPU
PANIC
TRANSMISSION
EEPROM RF CIRCUIT
SAW Resonator 308 MHz
CRYSTAL 4.19 MHz
figure 3.1 block diagram of the transmitter
- 3 -
4. Specification
4.1 CPU
Type
ROM
RAM
EEPROM
Clock frequency
Clock frequency generation
Package
uPD789860-xxx(8bit)
Manufacturer : NEC Corporation
4 Kbytes
128 bytes
32 bytes
4.19MHz
CRYSTAL Osillation
20pin SSOP
4.2 RF block
Carrer frequency
Frequency generation
Modulation
Bit transmission rate
Bandwidth
RF output power (field strength)
307.9MHz
SAW Resonator
FSK
1000bps or 500bps
100KHz
5000μ V/m at 3m
4.3 Others
Dimension
Weigh
Battery
Operation Voltage
Operation Temperature
56mm×35mm×11mm
22.4g
Lithium cell (CR2032)
Manufacturer : PANASONIC Battery corporation etc.
DC 3V
-20℃˜+60℃
- 4 -
5.Features
5.1 Transmission frame
The transmission begins immediately in case of LOCK and UNLOCK and PANIC button is pressed.
The transmission frame consists of the synchronous frame and the data frame. The synchronous frame
has 30 synchronous codes that it will be used for the receiver to wake up. The data frame consists of
24bit length identification code, 16bit security code and function code. 16million different identification codes
are available.
The security code is always changed in case of any of the buttons is pressed. The transmission time is
typically 640 milliseconds.
5.2 Battery saving
To prevent the battery exhaustion , the micro-computer of the transmitter is usually inactive. When the button
will be pressed, the micro-computer wakes up immediately and judges which button is pressing. Then the
micro-computer constructs the transmission frame and radiates it from the antenna .After transmitting , the
micro-computer switches stand-by mode by itself.
- 5 -