Electronic shelf label technology

An electronic shelf label is built from three things: an e-paper display that uses no power while it shows an image, a low-power radio that receives changes, and a coin cell that manufacturers rate at 5 to over 10 years with one or two updates a day. Everything else (sizes, colours, NFC, freezer versions) is a variation on that base.

This page gathers the technical decisions of the system in one place and points to a dedicated article where a topic needs more depth. The ranges come from manufacturer datasheets, manuals and certification documents, checked on 9 November 2026. When a figure belongs to a single manufacturer, we say so. If you want the basic definition, start with what an electronic shelf label is.

The whole system, from database to display

People talk about “the label”, but what you buy and maintain is a chain of four links. Knowing where each one sits keeps you from mistaking a radio problem for a software one.

 ERP / POS / PIM           Management platform            Gateway (access point)           Label
 ┌──────────────┐  API/    ┌───────────────────────┐ LAN  ┌──────────────────────────┐ radio ┌───────────┐
 │ price, stock │ ───────▶ │ maps product <-> ID   │ ───▶ │ translates and broadcasts│ ────▶ │ display   │
 │ promotions   │  file    │ update queue          │ PoE  │ (or sends infrared)      │ ◀──── │ + battery │
 └──────────────┘          └───────────────────────┘      └──────────────────────────┘  ack  └───────────┘
      company system             software                     in-store hardware          shelf hardware

• Source system. This is where the price is born. Neither the gateway nor the label calculates it; they only reproduce it.
• Management platform. It keeps the link between the product code and each label’s unique ID, and decides what is sent and when. It is software and falls outside this page: how a specific platform works is covered on keonex.com.
• Gateway or access point. It connects to the store network by cable (many are powered over PoE, such as the 48 V Waveshare unit described by CNX Software) and talks by radio to the labels in its zone. In Pricer’s system the equivalent is an infrared emitter fitted in the ceiling.
• Label. It receives, redraws and, in two-way systems, confirms receipt. If communication fails, it keeps the last value on screen.

The return arrow matters. Modern systems do not just broadcast: each label acknowledges receipt, which lets the platform know which labels are up to date. The Bluetooth ESL profile states this explicitly by building on a two-way transport.

Display: e-paper versus LCD

Nearly all the labels in the datasheets cited here use e-paper. It is a bistable technology: the image stays without power and energy is spent only at the moment of change (see the general description on Wikipedia). That is what makes a coin cell last for years, and it is also what limits the display: refresh is slow and colours are few.

LCD offers video and full colour but needs continuous power, so it runs on mains or a rechargeable battery. It is used in shelf strips and dynamic-content rails, not in the classic price tag. The detailed comparison, with criteria for choosing by store zone, is in e-paper versus LCD.

Radio: which band each manufacturer uses

There is more variety here than the market suggests. There are four families, and a single manufacturer may sell products in more than one.

Technology	Who documents it	What the source says
2.4 GHz, proprietary protocol	SoluM (Newton Pro), Vusion (2.6 F model), Hanshow (Nebular)	The Newton Pro sheet lists “ESL operating frequency 2.4 GHz”. Vusion’s is labelled 2.4GHz. Hanshow’s Nebular series manual describes 2.4 GHz wireless communication in the 2402-2480 MHz band, although the product page does not mention it
2.4 GHz, Bluetooth LE physical layer	Waveshare	According to CNX Software, the labels use Bluetooth 5.1 Low Energy (5.0 on the 2.9-inch model) plus NFC for close-range updates; the gateway joins the store network over dual-band Wi-Fi (2.4 and 5 GHz)
Sub-GHz	SoluM (SLG-EP101S gateway), Sertag	SoluM’s gateway lists 863-868 MHz for Europe, 902-928 MHz for the US and Canada, and 917-923.5 MHz for Korea. Sertag offers selectable 433, 868 and 915 MHz with a private protocol
Infrared	Pricer	Ceiling emitters that transmit “by fast flashes”; each label has a photosensor and answers with a flash

Why they all exist

The 2.4 GHz band is licence-free worldwide and the chips are cheap, but it shares space with Wi-Fi, Bluetooth and microwave ovens. Sub-GHz bands pass through shelving and obstacles better; Silicon Labs, which sells chips for ESL, cites range and penetration as the reasons for choosing them in one customer case. The trade-off is that each region has its own band, so the manufacturer must certify variants for Europe and for the Americas.

In the EU, radio equipment placed on the market has to meet the Radio Equipment Directive 2014/53/EU, which is why European variants of a sub-GHz label or gateway are certified separately. Ask the supplier for the declaration of conformity of the exact model, not of the product family.

Pricer, which has used infrared since 1991 by its own account, argues that this route sits above the congested ISM band. Its system needs line of sight between the ceiling emitter and the label and requires those emitters to be installed. That is a different building decision from hanging a wall gateway.

The Bluetooth standard

In February 2023 the Bluetooth SIG published the ESL profile on Bluetooth 5.4. It relies on a new feature, Periodic Advertising with Responses (PAwR), which allows low-power two-way communication in a one-to-many topology. According to the SIG, ESLs are organised in up to 128 groups of up to 255 labels, so one access point can address 32,640, and commands and responses are encrypted and authenticated with AES-CCM.

The promise is interoperability: labels from one maker and access points from another. Today that promise is more on paper than in stores, because the datasheets of the big manufacturers still describe proprietary protocols. If your tender requires interoperability, ask for it in writing, model by model, rather than assuming it because the chip is Bluetooth.

Gateways and coverage

The gateway determines how many labels a unit serves, what power it needs and how much it costs to cable the store. Public coverage data is thin: the only range we found from an identifiable source is the Waveshare gateway’s, 10 to 30 m indoors, and that is a developer product, not a large-store one. SoluM’s gateway publishes its bands and its 4.7 dBi external antenna, and its operating temperature of 0 to +40 °C, but no radius in metres on the pages we could read.

This is a question for the supplier, with your floor plan in hand, because real coverage depends on metal shelving, freezers and ceilings. How to size it and what to ask for in the quote is in gateways and access points.

Battery

Published figures sit in a narrow band and are easy to misread when separated from their test conditions.

Source	Cell	Published life	Condition
SoluM Newton Pro, single-cell models (sheet dated 28-11-2024)	1 × CR2450	Over 5 years	2 updates/day, 0-40 °C
SoluM Newton Pro, two-cell models	2 × CR2450	Over 10 years	2 updates/day, 0-40 °C
SoluM Newton Pro, freezer variants	2 × CR2450	Over 5 years	1 update/day, -25 to 0 °C
Vusion 2.6 F BW	2 × CR2450	5 years	1 update/day
Waveshare (CNX Software, 2025)	1,200 mAh	“About 5 years”	Manufacturer figure

Two useful readings. First: the second cell is how SoluM gets from 5 to over 10 years; the cost of that extra cell and any added thickness is something to ask the supplier. Second: SoluM’s freezer figure is half the ambient one even with two cells and fewer daily updates, which hints at what cold does to a battery. The sheets state this without quantifying it: frequent updates and low temperatures can shorten life.

How it is measured, what draws the most (radio, refresh or a colour display) and how to turn the manufacturer’s figure into your store’s figure is explained in battery life.

NFC

NFC on a label does not replace the radio. It is for identifying or configuring a label by tapping a phone or reader on it, and for updating a single one without infrastructure. The SoluM Newton Pro sheets list FeliCa (NFC Forum Type 3). Vusion’s 2.6 F announces active NFC and 128-bit AES encryption, and the Waveshare series offers it for local updates. When requesting quotes, find out whether NFC is standard across all sizes or only some, because the sheets we reviewed do not break it down by size.

Colours

An e-paper label can show black and white (BW), with red (BWR), with red and yellow (BWRY) and, in recent industry launches, more colours. SoluM’s Newton Pro sheet lists BWRY pixels for most of the range and BW for several freezer variants. Hanshow describes its Nebular Ultra range as “four-colour”.

More colour means slower refresh. Six-colour e-paper modules are advertised with a full refresh of about 15 seconds in a 3.6-inch module listing, an order of magnitude beyond black-and-white displays. A label that takes several seconds to change is no problem for a price, but it is for bulk changes if the system works sequentially. When red and yellow pay off (offers, expiry alerts) and when they do not is covered in BWR and BWRY colours.

Sizes

There is no single label size, there is a scale. This table draws on two published ranges, SoluM’s Newton Pro (17 sizes in the 2024 sheet, from 1.6 to 12.2 inches) and Hanshow’s Nebular (eight sizes per the manual, from 1.54 to 7.5 inches). The uses are indicative and set by the product type, not by the table.

Inches (range)	Published data	Typical use
1.5 to 1.9	SoluM 1.6 (200 × 200 px, 188 ppi); Hanshow 1.54	Small items and narrow shelves: jewellery, cosmetics, small hardware
2.2 to 2.9	SoluM 2.2, 2.6, 2.7 and 2.9; Hanshow 2.13, 2.66 and 2.9; freezer variants exist	The general-purpose size in grocery: price, unit price and little else
3.0 to 3.5	SoluM 3.5; Hanshow 3.5	More text: weight, origin, two prices
4.2 to 4.5	SoluM 4.2, 4.3 and 4.5; Hanshow 4.2	Gondola headers, textiles, product information
5.8 to 7.5	SoluM 5.8, 6.1 and 7.5; Hanshow 5.83 and 7.5	Headers, electronics, wine
9.7 to 12.2	SoluM 9.7, 11.6 and 12.2	Aisle signage, promotions, extended information

We found no datasheet with sizes above 12.2 inches within a shelf-label range, so we leave them out. SoluM publishes 188 ppi for the 1.6-inch label, 156 and 152 ppi for the 2.2 and 2.6, and around 100 ppi for the large formats. At the same pixel count, more inches means less sharpness.

One caution when comparing: the advertised size may be the display diagonal or the module’s, and manufacturers do not always say which. Ask for dimensions in millimetres and active area, as the SoluM and Hanshow sheets give them.

Cold variants

A standard SoluM label is rated for 0-40 °C (0-30 °C on some yellow models). Freezer variants are rated for -25 to 0 °C and, in the range we reviewed, exist only in certain sizes (2.2, 2.6, 2.9, 3.5 and 5.8 inches) and in black and white or reduced colours. Hanshow also states sub-zero versions (-25 to 0 °C, black and white only) in 2.13 and 2.66 inches according to its Nebular manual; one published copy of the manual adds the 3.5-inch size.

Cold affects three things: the battery (SoluM’s freezer model states half the life), the ink’s refresh speed, and condensation when cabinet doors are opened. What to check before fitting labels on a cold unit is in labels for cold and frozen.

What to ask before buying

1. Which band and protocol does each model use, and is there a variant certified for Europe?
2. Is the stated battery a replaceable cell? At how many updates a day and at what temperature?
3. How long does a full refresh take, in black and white and in colour?
4. What coverage does each gateway give on a floor plan like yours, with metal shelving and freezers?
5. Does it support the Bluetooth ESL profile, or do labels and gateways have to come from the same maker?
6. Is NFC across the whole range?

With those answers, the economics stop being an estimate. You can enter the data in the total cost calculator.

What this page does not cover

We do not describe any specific manufacturer’s hardware as a recommendation, and the figures quoted may change with new revisions of the datasheets. Integration with ERP, POS or e-commerce, user permissions and APIs are matters for the platform, not the label; that ground is covered by the texts on keonex.com. For the pharmacy sector, with its own software environment and regulation, the analysis is on farmaconnect.es.