U140-U compact black UHF RFID desktop reader/writer, underside with four rubber feet

U140-U Compact UHF RFID Desktop Reader/Writer, USB, EPC Gen2

The U140-U is a compact black USB reader/writer for EPC Gen2 (ISO 18000-6C) UHF tags, suited to back-office stations that encode and verify tags one at a time. It writes tags at up to 0.2 m, reads them at up to 0.5 m and sends tag data as USB keyboard input by default.

Frequency: 902–928 MHz (US band) or 920–925 MHz (China band); other regional bands on request
Cards / tags: EPC Gen2 UHF tags (read and write)
Interface: USB
Output: Keyboard emulation (USB HID)
Read range: Up to 0.5 m (depends on RF power, tag and environment)

Request a quote for U140-U Order a sample Datasheet (PDF)

✓ Sample units for evaluation
✓ Output format confirmed for your software
✓ Private label & OEM options
✓ Reply within 1 business day

Why integrators choose the U140-U

Compact black pad — a 15 mm thick housing with a light ring, meant for a back-office desk rather than a customer-facing counter.
Writes up to 0.2 m — encodes ISO 18000-6C / EPC Gen2 tags close to the pad and reads them back at up to 0.5 m.
Keyboard output by default — read results go straight into the active field; a virtual serial port build is available on request.
Adjustable radio — RF power from 12.5 to 26 dBm and FHSS or fixed-frequency operation, both set by software.
Shares the A140-U housing — the same compact enclosure as our 134.2 kHz animal-tag desktop reader.

Where the U140-U fits

The U140-U is meant for the back office rather than the front counter: an IT or facilities desk that writes UHF asset labels before equipment is deployed, a records room that tags files before they are shelved, or a card office that formats and writes batches of UHF cards before they go to reception. Its black, 15 mm compact housing with a light ring does not stand out among keyboards, docks and other PC equipment.

It uses the same housing as the A140-U 134.2 kHz animal-tag reader. The two read different tag technologies and cannot stand in for each other, but a site that uses both can stock one enclosure style.

A read, write, verify routine for encoding

Encoding at a desk works best as a short, repeatable routine:

Keep blank tags more than 0.5 m from the reader, or lower the RF power, so that only one tag is in the field.
Place one tag flat on the pad, within the 0.2 m write range.
Write the new data, for example the EPC number, from your host software.
Read the tag back and compare the result before moving it to the finished pile.

The write itself is started from host software that sends commands to the reader. Keyboard output only carries tag data into the host, so it can confirm a read but cannot start a write. Ask for the virtual serial port build if your software needs a COM port; the software and command documentation available for your build are confirmed in your quotation. For EPC, TID and user memory basics, see How to write UHF RFID tags.

U140-U specifications

General
Model	U140-U
Product type	UHF RFID desktop reader/writer
Form factor	Compact desktop pad with light ring
Color	Black

Tags & reading
Frequency	902–928 MHz (US band) or 920–925 MHz (China band); other regional bands on request
Air protocol	ISO 18000-6C / EPC Class 1 Gen 2
Supported tags	EPC Gen2 UHF tags (read and write)
Read range	Up to 0.5 m (depends on RF power, tag and environment)
Write range	Up to 0.2 m (depends on RF power, tag and environment)

Radio
Antenna	Built-in 2 dBi circularly polarized antenna
RF output power	12.5–26 dBm, software adjustable
Frequency hopping	FHSS or fixed frequency, set by software
Operating modes	Active mode and passive mode; answer mode available but not recommended

Interface & output
Interface	USB
Default output	Keyboard emulation (USB HID)
Optional build	USB virtual serial port (customized version)
Power	5 V DC from USB

Physical & environment
Thickness	15 mm
Operating temperature	-20 °C to +55 °C
Storage temperature	-40 °C to +85 °C

Specifications of U140-U as supplied for the standard version. Read range depends on the card or tag, mounting surface and environment — we can test your own cards before you order.

Download the U140-U datasheet (PDF, A4)

Card, tag and system compatibility

Works with

✓ISO 18000-6C / EPC Class 1 Gen 2 UHF labels, cards and inlays (read and write)
✓Keyboard input into any focused field (default build)
✓COM-port host software, through the USB virtual serial port build (on request)

Not designed for

✕134.2 kHz FDX-B and 125 kHz EMID animal tags — use the A140-U in the same housing
✕125 kHz and 13.56 MHz cards — see the 125kHz and 13.56MHz NFC readers
✕Writing tags from keyboard output alone (keyboard output only carries data into the host)
✕Connecting to an Android phone — use the U220-C USB-C UHF reader

Card not listed? Send us the card type or a photo and we will confirm compatibility before you buy.

Integration in 4 steps

1
Order the band build that is permitted where the reader will be used: 902–928 MHz or 920–925 MHz as standard.
2
Connect the U140-U by USB (5 V bus power). The default build types tag data like a keyboard; check it by reading a tag into a text editor.
3
For encoding, run your host software over the virtual serial port build and keep one tag within 0.2 m of the pad.
4
Read each tag back after writing to confirm the data before the tag is issued.

OEM / ODM options for U140-U

◆USB virtual serial port build for software-driven encoding, on request
◆Frequency band for the destination market: 902–928 MHz, 920–925 MHz or other regional bands on request
◆RF output preset within 12.5–26 dBm so that blank tags nearby stay out of the field, on request
◆Operating mode (active or passive) preset to suit your host software, on request
◆Your logo on the black top cover and private-label packaging, confirmed in your quotation

How OEM/ODM projects work →

Typical applications

U140-U FAQ

Can the U140-U write new EPC numbers to UHF tags?

Yes. The U140-U reads and writes ISO 18000-6C / EPC Gen2 tags, with a write range of up to 0.2 m. Writing is controlled by host software, not by keyboard output; the software and command documentation available for your build are confirmed in your quotation.

Why is the U140-U write range (0.2 m) shorter than its read range (0.5 m)?

A passive UHF tag needs more energy to write its memory than to answer a read, so writes need the tag closer to the antenna. Place the tag flat on the pad for encoding and read it back to confirm.

Is the U140-U the same as the A140-U?

Only the housing is shared. The A140-U reads 134.2 kHz FDX-B and 125 kHz EMID animal tags; the U140-U reads and writes EPC Gen2 UHF tags. Neither reads the other's tags.

Which parts of a UHF tag can I encode with the U140-U?

That depends on the host software rather than the radio. The U140-U is specified to read and write ISO 18000-6C / EPC Gen2 tags; which memory banks (EPC, user memory, passwords) and lock functions the software for your build can write is confirmed in your quotation. The TID bank is programmed by the chip maker and locked on most Gen2 chips, so it is read for checking, not encoded. Not every tag has user memory.