
DXT-21/EC 
DXT-23/EC
PORTABLE 
TRANSMITTERS
Operation Instructions
R&TTE VAEE 27682, EMC, SFT, ETS 
Linear Corporation declares that the apparatus DXT-21/EC & DXT-23/EC complies with 
the essential requirements and other relevant provisions of Directive 1995/5/EC.
(760) 438-7000 • FAX (760) 438-7043
www.linearcorp.com
)
The DXT-23/EC is a three-button, four-code transmitter. Pressing 
either of the transmitter’s front buttons sends codes one and two. 
Pressing the small button on the transmitter’s top sends code 
three. Pressing both front buttons together sends code four.
RED INDICATOR 
LIGHTS WHEN 
TRANSMITTING
DXT-23/EC FEATURES
PRESS LEFT BUTTON FOR CODE 1 
PRESS RIGHT BUTTON FOR CODE 2
BY
PRESS TOP BUTTON 
FOR CODE 3
The DXT-21/EC and DXT-23/EC are battery powered portable 
transmitters designed for use with Linear’s DX Format receivers 
at the same frequency. Each transmitter can be used in a limitless 
number of wireless remote control applications. Pressing a button 
on the transmitter sends a digitally coded wireless signal to its 
companion receiver.
The digital DX code format features over a million possible codes. 
The DX transmitters are precoded at the factory to unique codes, so 
no field coding is required. Transmitters can send a signal for up to 
10 seconds per activation.
For versatility, any transmitter code can be programmed into any 
receiver channel. Receivers must be programmed to the 
transmitter code before system testing and operation. Refer to the 
receiver’s instructions for details on programming.
Each transmitter is powered from two 3-Volt #2032 lithium 
batteries with an expected battery life of up to 5 years. The red 
test/operate indicator lights during operation and can be viewed 
from the front or the top of the unit. The indicator will glow dimly 
during operation when the batteries get low. It will stop lighting 
altogether during operation when the batteries are below 4.5 volts.
A removable pocket clip and belt clip are provided for each 
transmitter. Either can be attached to the back of the transmitter 
allowing the unit to be clipped to shirt pocket or slid onto a belt.
The top button on each transmitter can be hidden with the top 
button cover supplied with each unit.
BATTERY REPLACEMENT POCKET & BELT CLIP INSTALLATION
REMOVE BATTERY 
ACCESS SCREW
FLIP 
TRANSMITTER 
OVER
PRODUCT DESCRIPTION
The DXT-21/EC is a two-button, one-code transmitter. Pressing
DXT-21/EC FEATURES
either the round button on the transmitter’s front, or the small 
button on the transmitter’s top will send the same signal.
PRESS EITHER BUTTON 
TO SEND CODE 1
RED INDICATOR 
LIGHTS WHEN 
TRANSMITTING
PRESS BUTTONS FOR A 
MINIMUM OF 2 SECONDS
ATTACH WITH 
THREE SCREWS
BELT 
CLIP
BUTTON COVER INSTALLATION LINEAR LIMITED WARRANTY
REMOVE FOUR 
SCREWS TO 
OPEN CASE
REPLACE WITH 
COVER PLATE
PRESS BOTH 
FRONT 
BUTTONS FOR 
CODE 4 
(FOR ADDED 
SECURITY)
PRESS BUTTONS FOR A 
MINIMUM OF 2 SECONDS
REMOVE 
TOP BUTTON
SWING BATTERY 
COMPARTMENT OPEN
REPLACE 
WITH TWO 
TYPE 2032 
BATTERIES
This Linear product is warranted against defects in material and workmanship for twelve 
(12) months. The Warranty Expiration Date is labeled on the product. This warranty 
extends only to wholesale customers who buy direct from Linear or through Linear’s 
normal distribution channels. Linear does not warrant this product to consumers. 
Consumers should inquire from their selling dealer as to the nature of the dealer’s 
warranty, if any. There are no obligations or liabilities on the par t of Linear
Corporation for consequential damages arising out of or in connection with use 
or performance of this product or other indirect damages with respect to loss of 
property, revenue, or profit, or cost of removal, installation, or reinstallation. All
implied warra nties, includ ing implied warranties for merchantability and implied 
warranties for fitness, are valid only until Warranty Expiration Date as labeled on the 
product. This Linear Corporation Warranty is in lieu of all other warranties express
or implied.
All products returned for warranty service require a Return Product Authorization 
Number (RPA#). Contact Linear Technical Services at 1-800-421-1587 for an 
RPA# and other important details.
Linear radio controls provide a reliable communications link and fill an important need 
in portable wireless signalling. However, there are some limitations which must be 
observed.
1 For U.S. installations only: The radios are required to comply with FCC Rules and
Regulations as Part 15 devices. As such, they have limited transmitter power and 
therefore limited range.
1 A receiver cannot respond to more than one transmitted signal at a time and may
be blocked by radio signals that occur on or near their operating frequencies, 
regardless of code settings. 
1 Changes or modifications to the device may void FCC compliance.
1 Infrequently used radio links should be tested regularly to protect against
undetected interference or fault.
1 A general knowledge of radio and its vagaries should be gained prior to acting as
a wholesale distributor or dealer, and these facts should be communicated to the 
ultimate users.
IMPORTANT !!!
SIDE UP
ATTACH WITH 
TWO SCREWS
POCKET 
CLIP
This Linear product is warranted against defects in material and workmanship for twelve (12) 
months. The Warranty Expiration Date is labeled on the product. This warranty extends only 
to wholesale customers who buy direct from Linear or through Linear’s normal distribution 
channels. Linear does not warrant this product to consumers. Consumers should inquire 
from their selling dealer as to the nature of the dealer’s warranty, if any. There are no obligations
or liabilities on the part of Linear Corporation for consequential damages arising out of 
or in connection with use or performance of this product or other indirect damages with 
respect to loss of prope rty, revenue, or profit , or cost of removal, installation, or 
reinstallation. All implied warranties, including implied warranties for merchantability and 
implied warranties for fitness, are valid only until Warranty Expiration Dat e as labeled on 
the product. This Linear Corporation Warranty is in lieu of all other warranties express or 
implied. For warranty service on Linear equipment return product , at sender’s expense 
to:
Linear Hong Kong 19/F Hounor Industrial Centre, 6 Sun Yip Street Chai Wan, Hong Kong 
Attention: Repairs Department
REPAIRS POLICY
Charges will be made for equipment that is not in warranty, shows customer abuse, or is damaged 
by the effects of lightning, water, fire, or other abnormal happenings. 
Customer’s equipment sent in for repair may be repaired or replaced with new or remanufactured 
equipment at Linear’s discretion. 
The customer is always responsible for shipping and handling charges to the repairs facility. 
Linear will pay return shipping and handling charges on “in warranty” products shipped back to 
the customer. The customer will be billed for the return shipping and handling charges on “out of 
warranty” products. 
There will be a 50% expedite fee for any express requests. 
The International Sales Manager must be notified prior to the return of product to Linear. All 
international returns must have an International Repair Authorization number (IRA #). The number 
must be marked on all packages. Failure to do so will cause delays in processing.
IMPORTANT !!!
Linear radio controls provide a reliable communications link and fill an important need in portable 
wireless signaling. However, there are some limitations which must be observed. The radios are 
required to comply with local rules and regulations as radio devices. A s such, they have limited 
transmitter power and therefore limited range. 
A receiver cannot respond to more than one transmitted signal at a time and may be blocked by 
radio signals that occur on or near their operating frequencies, regardless of code settings. 
Changes or modifications to the device may void regulatory compliance. Infrequently used radio 
links should be tested regularly to protect against undetected interference or fault. A general 
knowledge of radio and its vagaries should be gained prior to acting as a wholesale distributor 
or dealer, and these facts should be communicated to the ultimate users. 
Copyright © 2003 Linear Corporation  212625 B
INTERNATIONAL WARRANTY