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Adjusting the Read Range (Power) on the TSL 1128 RFID Scanner

Lower the 1128 scanner's output power with a microSD configuration file so it only reads nearby tags.

Written by Hrant Minasyan

By default, the 1128 Bluetooth® UHF RFID Reader scans at full power (29 dBm). At full power it can pick up tags from neighboring racks, carts, or staging areas you didn't intend to scan. Lowering the power shortens the read range so the scanner only reads items close to it.

The setting is stored in a small configuration file on a microSD card inside the scanner, and the scanner applies it automatically every time it powers on or wakes from sleep.

What you'll need:

  • A microSD card (SD/SDHC, formatted FAT16 or FAT32, up to 32 GB)

  • A computer with a microSD card reader

  • The 1128 scanner

Step 1: Create the configuration file

  1. On your computer, open a plain text editor (Notepad on Windows, or TextEdit on Mac set to Format -> Make Plain Text).

  2. Type the following line, replacing 20 with the power level you want (see the table in Step 2): .iv -n -o20

  3. Save the file with the name AUTO.TXT.

Important: Make sure the file is named exactly AUTO.TXT and not AUTO.TXT.txt. On Windows, turn on View -> File name extensions to check.

Step 2: Choose your power level

The power value can be set from 10 (shortest range) to 29 (maximum range, factory default).

Setting

Range

Best for

-o29

Maximum (default)

Full warehouse counts, large open areas

-o25

Medium-long

General check-in / check-out

-o20

Medium

Scanning a single cart or pallet

-o15

Short

Scanning one shelf or a small group of items

-o10

Minimum

Scanning a single item up close

Read distance also depends on tag type, surrounding materials (metal and liquids reduce range), and how items are stacked. We recommend starting at 20 and adjusting up or down in steps of 2–3 until you get the result you want.

Step 3: Copy the file to the microSD card

  1. Insert the microSD card into your computer.

  2. Copy AUTO.TXT to the root of the card (not inside any folder).

  3. Safely eject the card.

Step 4: Install the card in the scanner

  1. Turn off the scanner and remove the battery.

  2. Inside the battery compartment, find the slot marked "Insert MicroSD card here."

  3. Slide the microSD card into the slot, then push and release it once to lock it in place. The slot is spring-loaded.
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  4. Reinsert the battery and turn the scanner back on. The new power setting is applied automatically at startup.

To remove the card: push and release it once more to eject it, then pull it out of the slot.

Step 5: Test the range

  1. Connect the scanner to the Rentopian RFID app as usual (see Connecting RFID Device).

  2. Open an order or return page and scan a few tagged items at different distances.

  3. If the range is too short or too long, edit the number in AUTO.TXT, copy it back to the card, and restart the scanner.

Changing back to full power

Delete AUTO.TXT from the card, change the value to -o29, or remove the card entirely, then restart the scanner.

Notes

  • Leave the microSD card in the scanner. Without it, the scanner returns to full power on the next restart.

  • The scanner may also create a file called LOG.TXT on the card. This is normal and can be ignored or deleted.

  • The -n in the command tells the scanner to save the setting without starting a scan, so don't remove it.

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