WIRELESS MADE SIMPLE
®
OEM KEYFOB TRANSMITTER DATA GUIDE
DESCRIPTION
The Linx CMD-KEY#-***-xxx Keyfob
transmitter is ideal for general-purpose
remote control and command applications. It
has been pre-certified for FCC Part 15,
Industry Canada, and European CE
(433MHz only) compliance, reducing
development costs and time to market.
Available in 315, 418 (standard), or
433.92MHz, this stylish and compact remote
has a range of up to 750 feet when combined
with the LR Series receiver. The Keyfob can
be configured with 1 to 5 buttons and the
keypad and labeling can be modified to meet
specific customer requirements. Selectable
addressing provides security and allows the
creation of up to 1,024 distinct transmitter-
receiver relationships. The Keyfob is
available in black, white, or translucent
colors. The transmission can be decoded
using a matching Linx Function Module, KH
Series receiver / decoder, or an LR or LT
Series receiver paired with a decoder IC or
microcontroller. The unit operates from a
single 3V CR2032 lithium button cell.
1.00"
S4
S1 S5 S3
S2
2.23"
1.37"
0.45"
Figure 1: Package Dimensions
FEATURES
n
n
n
n
n
n
n
n
n
n
n
FCC, Canada, and CE pre-certified
1 to 5 buttons
Small package
Customizable keypad
General Remote Control
Keyless Entry
Garage / Gate Openers
Lighting Control
Call Systems
Home / Industrial Automation
Wire Elimination
OEM Configurations
With a one-time NRE and minimum
order, Linx can configure the keypad
and label areas to meet your specific
requirements. Contact Linx for details.
APPLICATIONS INCLUDE
ORDERING INFORMATION
PART #
DESCRIPTION
CMD-KEY#-***-xxx
Keyfob Transmitter
EVAL-***-KEY#
Keyfob Basic Evaluation Kit
# = Number of Buttons: 1 to 5
*** = 315, 418 (Standard), 433.92 MHz
xxx = Color Leave blank for standard Black
WHT = White
CGY= Gray
CBL = Blue
CRE = Red
CPU = Purple
Revised 01/19/10
ELECTRICAL SPECIFICATIONS
Parameter
POWER SUPPLY
Operating Voltage
Supply Current
Power-Down Current
TRANSMITTER SECTION
Transmit Frequency Range:
CMD-KEY#-315
CMD-KEY#-418
CMD-KEY#-433
Center Frequency Accuracy
ENVIRONMENTAL
Operating Temperature Range
–
–
Designation
V
CC
I
CC
I
PDN
F
C
–
–
–
-50
-40
315
418
433.92
–
–
–
–
–
+50
+85
MHz
MHz
MHz
kHz
°C
–
–
–
–
1
Min.
2.1
–
–
Typical
3.0
3.4
5.0
Max.
3.6
–
–
Units
VDC
mA
nA
Notes
–
–
1
SETTING THE TRANSMITTER ADDRESS
The Keyfob allows the selection of one
of 1,024 unique addresses. All keyfobs
are supplied set to the same address.
To avoid contention with other units or
to create unique relationships, the
address can be changed. This is
accomplished by cutting the traces with
a sharp object, such as an X-Acto knife.
The traces are accessed by removing
the rear cover.
If the trace is intact, the address line is
Figure 2: DIP Switch Assignments
connected to ground, otherwise it is
floating. The receiver’s address must match exactly in order for the units to
communicate. Application Note AN-00300 describes in detail how to set the
address to match any of the receivers offered by Linx. This note can be found in
the Support section of the Linx website, www.linxtechnologies.com.
Notes
1. Characterized, but not tested
BUTTON ASSIGNMENTS
THEORY OF OPERATION
The CMD-KEY#-*** Keyfob transmitter combines the LR Series transmitter with
an on-board Holtek HT640 encoder IC to form a simple, yet effective, RF remote
control transmitter. The LR transmitter is a low-cost, high-performance,
synthesized ASK / OOK transmitter. The transmitter’s synthesized architecture
delivers outstanding stability and frequency accuracy while minimizing the effects
of antenna port loading and mismatching. This reduces or eliminates frequency
pulling, bit contraction, and other negative effects common to SAW-based
transmitter architectures, providing a significantly higher level of performance
and reliability.
When a button is pressed on the transmitter, power is applied to the internal
circuitry and the encoder IC is enabled. The encoder detects the logic states of
the address lines and button data lines. These states are formatted into a three-
word transmission cycle that continues until the button is released. The encoder
data is used to modulate the transmitter, which, through the antenna, conveys
the data into free space. On the receiver side, a decoder IC or custom
microcontroller is used to check the transmitter’s address bits against the
address settings of the receiving device. If a match is confirmed, the decoder’s
outputs are set to replicate the transmitter’s button states. These outputs can
then be used to activate external circuitry required by the application.
The transmitter is compatible with several Linx receiver products, including the
LR, KH2, LT, and OEM product families. For applications where range is critical,
the LR Series receiver is the best choice due to its outstanding sensitivity. When
the transmitter is combined with an LR Series receiver and the HT658 decoder
chip, ranges of up to 750 feet are possible. Applications operating over shorter
distances will also benefit from the increased link reliability and superior noise
immunity provided by the LR Series receiver.
The Keyfob is available in five unique button configurations. Those
configurations and the corresponding switch numbers are shown in the figure
below. The table shows which encoder data line has been assigned to each
switch. When a button is pressed, the data line will go high, causing the
corresponding data line on the decoder to go high if the addresses match.
S4
S5
S2
S4
S5
S2
Button
S4
S1
S2
S3
S4
S1 S5 S3
S2
Data Line
D0
D1
D2
D3
D4
S1
S2
S3
S4
S5
Figure 3: CMD-KEY#-*** Button Assignments
Page 2
Page 3
CONTENTION CONSIDERATIONS
It is important to understand that only one transmitter at a time can be activated
within a reception area. While the transmitted signal consists of encoded digital
data, only one carrier of any particular frequency can occupy airspace without
contention at any given time. If two transmitters are activated in the same area
at the same time, then the signals will interfere with each other and the decoder
will not see a valid transmission, so it will not take any action.
COMPLIANCE REQUIREMENTS
The CMD-KEY#-*** has been pre-certified by Linx Technologies for FCC Part 15
and Industry Canada RSP-100 compliance. The 433.92MHz version has also
been tested for CE compliance for use in the European Union. The 315MHz and
418MHz versions are not legal for use in Europe.
LABELING / INSTRUCTION REQUIREMENTS
The CMD-KEY#-*** Keyfob Transmitter has already been labeled in accordance
with FCC, Industry Canada, and CE regulations in effect as of the date of this
document. No further labeling of the unit is needed; however, it is necessary to
include the following statement in the end product’s instruction manual or insert
card for FCC compliance. Industry Canada only requires the shaded portion. EU
does not require a statement.
BATTERY REPLACEMENT
The remote unit utilizes a standard CR2032 lithium
button cell. In normal use, it will provide 1 to 2 years of
operation. Access for replacement is accomplished by
gently prying apart the two halves of the keyfob at the
seam (fingernails will do for this). Once the unit is
open, remove the battery by sliding it out from beneath
the retainer.
There may be the risk of explosion if the battery is
replaced by the wrong type. Replace it with the same
type of battery while observing the polarity shown in
the adjacent figure.
Battery
+
INSTRUCTION TO THE USER
This device complies with Part 15 of the FCC Rules.
Operation of this device 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.
This equipment has been tested and found to comply with the limits for a Class
B digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or more of
the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
This equipment has been certified to comply with the limits for a Class B
computing device, pursuant to FCC Rules. In order to maintain compliance with
FCC regulations, shielded cables must be used with this equipment. Operation
with non-approved equipment or unshielded cables is likely to result in
interference to radio and TV reception. The user is cautioned that changes and
modifications made to the equipment without the approval of manufacturer
could void the user’s authority to operate this equipment.
Figure 4: Battery Access
ASSEMBLY DIAGRAM
Figure 5: CMD-KEY#-*** Assembly
Page 4
Place the above statement in the instruction manual or insert card.
Page 5
CUT TRACE FOR
ADDRESS
SELECT
There are four options for receivers within the Linx
product line. The first option is to use one of the OEM
Function Modules, such as the Relay Module or the AC
Wall Module. These items are also pre-certified and
can be immediately included in a product.
The other options are to use one of the Linx receiver
modules. The signal sent by the Keyfob transmitter can
be received by the LR Series receiver module or the LT
Series transcever module. These modules can be
connected to the Holtek HT658 decoder to decode the
signal, or a custom microcontroller can be programmed
to decode it and take specific action.
The KH2 Series offers a slightly simpler solution by
combining the LR Series receiver and the HT658
decoder in a single package.
When a button is pressed on the transmitter, a
corresponding line on the decoder will go high (as long
as the addresses match). This can then be connected
to whatever circuitry is required by the application.
Application Note AN-00300 discusses in detail how to
set the addresses on all of the units. Data guides for all
of the receivers, the HT640 encoder, and the HT658
decoder can be found on the Linx Technologies
website, www.linxtechnologies.com.
VCC
GND
RECEIVERS
B1
D1
D2
D3
D4
D5
D6
D7
DOUT
TE
OSC2
OSC1
GND
VCC
D0
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
24
23
22
21
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
9
10
11
12
390k
R4
GND
HT640
U1
VCC
VCC
GND
IADJ/VCC
DATA IN
RF OUT
TOUCHPAD
TYPICAL APPLICATIONS
The outstanding sensitivity of the LR
Series receiver offers the best range
when combined with the Keyfob
transmitter. When using the LR
Series receiver, the Holtek HT658
decoder chip should be connected
to decode the received signal. This
decoder has ten address lines that
must match the Keyfob address
lines. A DIP switch is commonly
used to set these, but they can also
be hardwired. As long as the
address lines match, when a button
on the Keyfob is pressed, a
corresponding data line on the
decoder (D0-D4) will go high. These
data lines can then be connected to
external circuitry to perform
whatever function is required by the
application.
GND
PDN
VCC
GND
TOUCHPAD
S5
VCC
VCC
GND
RXM-LR
VCC
1
2
3
4
5
6
7
8
9
10
11
12
GND
D1
D2
D3
D4
D5
D6
D7
VT
DIN
OSC1
OSC2
GND
HT658
GND
VCC
D0
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
24
23
22
21
20
19
18
17
16
15
14
13
TOUCHPAD
TOUCHPAD
R1
390k
TOUCHPAD
S1
S2
S3
Figure 7: CMD-KEY#-*** Schematic Diagram
Page 6
Page 7
VCC
Figure 6: LR Receiver and HT658 Schematic
S4
Set
For FCC
Compliance
GND
GND
R1
1
2
3
4
5
6
7
8
NC
NC
NC
GND
VCC
PDN
RSSI
DATA
ANT
GND
NC
NC
NC
NC
NC
NC
16
15
14
13
12
11
10
9
GND
TXM-LR
GND
GND
WIRELESS MADE SIMPLE
®
U.S. CORPORATE HEADQUARTERS
LINX TECHNOLOGIES, INC.
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
www.linxtechnologies.com
Disclaimer
Linx Technologies is continually striving to improve the quality and function of its products. For this reason,
we reserve the right to make changes to our products without notice. The information contained in this Data
Guide is believed to be accurate as of the time of publication. Specifications are based on representative lot
samples. Values may vary from lot-to-lot and are not guaranteed. "Typical" parameters can and do vary over
lots and application. Linx Technologies makes no guarantee, warranty, or representation regarding the
suitability of any product for use in any specific application. It is the customer's responsibility to verify the
suitability of the part for the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY
APPLICATION WHERE THE SAFETY OF LIFE OR PROPERTY IS AT RISK.
Linx Technologies DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF
CUSTOMER'S INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE
OR NON-CONFORMING PRODUCTS OR FOR ANY OTHER BREACH OF CONTRACT BY LINX
TECHNOLOGIES. The limitations on Linx Technologies' liability are applicable to any and all claims or
theories of recovery asserted by Customer, including, without limitation, breach of contract, breach of
warranty, strict liability, or negligence. Customer assumes all liability (including, without limitation, liability
for injury to person or property, economic loss, or business interruption) for all claims, including claims
from third parties, arising from the use of the Products. The Customer will indemnify, defend, protect, and
hold harmless Linx Technologies and its officers, employees, subsidiaries, affiliates, distributors, and
representatives from and against all claims, damages, actions, suits, proceedings, demands, assessments,
adjustments, costs, and expenses incurred by Linx Technologies as a result of or arising from any Products
sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for
losses arising from the use or failure of the device in any application, other than the repair, replacement, or
refund limited to the original product purchase price. Devices described in this publication may contain
proprietary, patented, or copyrighted techniques, components, or materials. Under no circumstances shall
any user be conveyed any license or right to the use or ownership of such items.
© 2010 by Linx Technologies, Inc. The stylized Linx logo,
Linx, “Wireless Made Simple”, CipherLinx, and the stylized
CL logo are the trademarks of Linx Technologies, Inc.
Printed in U.S.A.
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