WIRELESS MADE SIMPLE ®
OEM KEYFOB TRANSMITTER DATA GUIDE
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 1.00"
(433MHz only) compliance, reducing S1 S5 S3
development costs and time to market. 2.23"
Available in 315, 418 (standard), or S2
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 1.37" 0.45"
keypad and labeling can be modified to meet
specific customer requirements. Selectable
addressing provides security and allows the Figure 1: Package Dimensions
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.
FEATURES OEM Configurations
n FCC, Canada, and CE pre-certified With a one-time NRE and minimum
n 1 to 5 buttons order, Linx can configure the keypad
n Small package and label areas to meet your specific
n Customizable keypad requirements. Contact Linx for details.
APPLICATIONS INCLUDE ORDERING INFORMATION
n General Remote Control PART # DESCRIPTION
n Keyless Entry CMD-KEY#-***-xxx Keyfob Transmitter
n Garage / Gate Openers EVAL-***-KEY# Keyfob Basic Evaluation Kit
n # = Number of Buttons: 1 to 5
Lighting Control *** = 315, 418 (Standard), 433.92 MHz
n Call Systems xxx = Color Leave blank for standard Black
n Home / Industrial Automation WHT = White CGY= Gray CBL = Blue
n Wire Elimination CRE = Red CPU = Purple
ELECTRICAL SPECIFICATIONS SETTING THE TRANSMITTER ADDRESS
Parameter Designation Min. Typical Max. Units Notes The Keyfob allows the selection of one
POWER SUPPLY of 1,024 unique addresses. All keyfobs
Operating Voltage VCC 2.1 3.0 3.6 VDC – are supplied set to the same address.
Supply Current ICC – 3.4 – mA – To avoid contention with other units or
Power-Down Current IPDN – 5.0 – nA 1 to create unique relationships, the
TRANSMITTER SECTION address can be changed. This is
Transmit Frequency Range: FC accomplished by cutting the traces with
CMD-KEY#-315 – 315 – MHz – a sharp object, such as an X-Acto knife.
CMD-KEY#-418 – 418 – MHz – The traces are accessed by removing
CMD-KEY#-433 – 433.92 – MHz – the rear cover.
Center Frequency Accuracy – -50 – +50 kHz – If the trace is intact, the address line is Figure 2: DIP Switch Assignments
ENVIRONMENTAL connected to ground, otherwise it is
Operating Temperature Range – -40 – +85 °C 1 floating. The receiver’s address must match exactly in order for the units to
Notes communicate. Application Note AN-00300 describes in detail how to set the
1. Characterized, but not tested 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.
THEORY OF OPERATION The Keyfob is available in five unique button configurations. Those
The CMD-KEY#-*** Keyfob transmitter combines the LR Series transmitter with configurations and the corresponding switch numbers are shown in the figure
an on-board Holtek HT640 encoder IC to form a simple, yet effective, RF remote below. The table shows which encoder data line has been assigned to each
control transmitter. The LR transmitter is a low-cost, high-performance, switch. When a button is pressed, the data line will go high, causing the
synthesized ASK / OOK transmitter. The transmitter’s synthesized architecture corresponding data line on the decoder to go high if the addresses match.
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. S4
When a button is pressed on the transmitter, power is applied to the internal S4
circuitry and the encoder IC is enabled. The encoder detects the logic states of S5 S5
the address lines and button data lines. These states are formatted into a three- S2 S2
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. Button Data Line
The transmitter is compatible with several Linx receiver products, including the S1 D0
LR, KH2, LT, and OEM product families. For applications where range is critical, S4 S4
the LR Series receiver is the best choice due to its outstanding sensitivity. When S1 S3 S1 S5 S3 S2 D1
the transmitter is combined with an LR Series receiver and the HT658 decoder S2 S3 D2
chip, ranges of up to 750 feet are possible. Applications operating over shorter S2
distances will also benefit from the increased link reliability and superior noise S4 D3
immunity provided by the LR Series receiver. S5 D4
Figure 3: CMD-KEY#-*** Button Assignments
Page 2 Page 3
CONTENTION CONSIDERATIONS COMPLIANCE REQUIREMENTS
It is important to understand that only one transmitter at a time can be activated The CMD-KEY#-*** has been pre-certified by Linx Technologies for FCC Part 15
within a reception area. While the transmitted signal consists of encoded digital and Industry Canada RSP-100 compliance. The 433.92MHz version has also
data, only one carrier of any particular frequency can occupy airspace without been tested for CE compliance for use in the European Union. The 315MHz and
contention at any given time. If two transmitters are activated in the same area 418MHz versions are not legal for use in Europe.
at the same time, then the signals will interfere with each other and the decoder LABELING / INSTRUCTION REQUIREMENTS
will not see a valid transmission, so it will not take any action.
BATTERY REPLACEMENT 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
The remote unit utilizes a standard CR2032 lithium document. No further labeling of the unit is needed; however, it is necessary to
button cell. In normal use, it will provide 1 to 2 years of include the following statement in the end product’s instruction manual or insert
operation. Access for replacement is accomplished by card for FCC compliance. Industry Canada only requires the shaded portion. EU
gently prying apart the two halves of the keyfob at the does not require a statement.
seam (fingernails will do for this). Once the unit is
open, remove the battery by sliding it out from beneath +
the retainer. INSTRUCTION TO THE USER
There may be the risk of explosion if the battery is Battery This device complies with Part 15 of the FCC Rules.
replaced by the wrong type. Replace it with the same Operation of this device is subject to the following two conditions:
type of battery while observing the polarity shown in Figure 4: Battery Access (1) This device may not cause harmful interference, and
the adjacent figure.
(2) this device must accept any interference received, including interference
ASSEMBLY DIAGRAM 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 5: CMD-KEY#-*** Assembly Place the above statement in the instruction manual or insert card.
Page 4 Page 5
There are four options for receivers within the Linx ADDRESS SELECT
product line. The first option is to use one of the OEM CUT TRACE FOR
Function Modules, such as the Relay Module or the AC
Wall Module. These items are also pre-certified and VCC
can be immediately included in a product.
The other options are to use one of the Linx receiver B1
modules. The signal sent by the Keyfob transmitter can VCC GND
be received by the LR Series receiver module or the LT 24 23 22 21 20 19 18 17 16 15 14 13
Series transcever module. These modules can be
connected to the Holtek HT658 decoder to decode the VCC D0 A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
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 DOUT OSC2 OSC1 GND HT640
decoder in a single package. U1 D1 D2 D3 D4 D5 D6 D7 TE
When a button is pressed on the transmitter, a
corresponding line on the decoder will go high (as long 1 2 3 4 5 6 7 8 9 10 11 12
as the addresses match). This can then be connected GND
to whatever circuitry is required by the application.
Application Note AN-00300 discusses in detail how to R4 390k
set the addresses on all of the units. Data guides for all VCC GND
of the receivers, the HT640 encoder, and the HT658
decoder can be found on the Linx Technologies
TYPICAL APPLICATIONS PDN VCC GND RF OUT
The outstanding sensitivity of the LR
Series receiver offers the best range DATA IN IADJ/VCC
when combined with the Keyfob 1 16 GND GND TXM-LR
transmitter. When using the LR 2 NC ANT 15
3 NC GND 14
Series receiver, the Holtek HT658 VCC 4 NC NC 13
5 GND NC 12 GND
decoder chip should be connected 6 VCC NC 11
7 PDN NC 10
to decode the received signal. This GND 8 RSSI NC 9 Set For FCC Compliance
DATA NC GND GND
decoder has ten address lines that RXM-LR R1
must match the Keyfob address
lines. A DIP switch is commonly VCC VCC
used to set these, but they can also 1 D1 VCC 24
2 D2 D0 23
be hardwired. As long as the 3 D3 A9 22
4 D4 A8 21
address lines match, when a button 5 D5 A7 20
6 D6 A6 19
on the Keyfob is pressed, a 7 D7 A5 18
8 VT A4 17
corresponding data line on the 9 DIN A3 16
10 OSC1 A2 15
decoder (D0-D4) will go high. These 11 OSC2 A1 14
data lines can then be connected to R1 12 GND A0 13 TOUCHPAD TOUCHPAD TOUCHPAD TOUCHPAD TOUCHPAD
390k GND HT658
external circuitry to perform GND
whatever function is required by the S1 S2 S3 S4 S5
application. Figure 6: LR Receiver and HT658 Schematic VCC
Figure 7: CMD-KEY#-*** Schematic Diagram
Page 6 Page 7
WIRELESS MADE SIMPLE ®
U.S. CORPORATE HEADQUARTERS
LINX TECHNOLOGIES, INC.
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
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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